Coincidence or not, during the "Chinese exclusion" era (between 1880 and 1943) San Francisco was rather static while Los Angeles is the one that grew dramatically.

In 1880 Los Angeles was still a small town, with only about 10,000 inhabitants, compared with more than 60,000 in San Francisco and more than 20,000 in Sacramento. Even Monterey was bigger than Los Angeles. The whole of southern California (six counties from Los Angeles to San Diego) had less than 50,000 residents. The arrival of the transcontinental railroad in 1876 changed all that.

The Los Angeles Times was founded in 1881 by Nathan Cole and Thomas Gardiner. In 1879 Robert Widney established a private university, the University of Southern California, predating Stanford as the first private university of California, on land donated by bankers Isaias Hellman, Ozro Childs (a former 49er) and John Downey. In 1882 a southern branch of the California State Normal School opened in Los Angeles, which later became the Los Angeles branch of the University of California, UCLA. In 1888 a real City Hall opened in Los Angeles (until then the mayor had simply resided in a rented homes and hotels).

Two competing transcontinental railroads had made it easier and cheaper to travel to southern California: the Southern Pacific Railroad of the "Big Four", that connected Los Angeles to San Francisco in September 1876 (when Los Angeles had fewer than 10,000 people) and the Atchison, Topeka and Santa Fe Railroad, that connected Los Angeles to Chicago in May 1887 (when Los Angeles had about 40,000 people). Their fare war caused the price of a ticket from Kansas City to Los Angeles to crash to one dollar, and their marketing of sunny weather, ocean views and cheap land attracted the first wave of immigrants from the Midwest. In 1883 the Southern Pacific extended the San Francisco to Los Angeles line to New Orleans, creating a third transcontinental route.

Tens of thousands of families could suddenly afford to move to southern California. Among the immigrants were thousands of people afflicted by illnesses who hoped that the climate of southern California would heal them: for the first time in history a frontier was being settled by the sick and the retirees. In 1890 Jerome Madden, working for the Southern Pacific Railroad, published a book on "California - its attractions for the invalid, tourist, capitalist and homeseeker".

Realtors popped up everywhere trying to sell land to investors from other states. In 1887 the first electric railway started operating in Los Angeles specifically to help sell land on Pico Street, which was far from downtown. Moses Sherman was the man who electrified Los Angeles' streets: in 1890 he founded the Los Angeles Consolidated Electric Railway Company (LACE) that quickly built electric lines crisscrossing the county.

The other magnet of southern California was the orange tree. For centuries, from the missions to the ranches to the Chinese farms, wheat had been the main crop grown in California. Around 1855 California's wheat output started exceeding local consumption and wheat could easily be exported because it did not require refrigeration. Legend has it that the first citrus orchard was planted in 1804 at the San Gabriel Mission, east of Los Angeles. In 1833 a Santa Fe fur trapper, William Wolfskill, settled in Los Angeles, and in 1838 started a vineyard, moving on, in 1841, to cultivating oranges, creating a popular hybrid, the Valencia orange. Twenty years later, the majority of California’s orange trees were in Wolfskill’s orchards. In 1877 his son Joseph was the first one to ship oranges by train to another state, thanks to the newly inaugurated Southern Pacific Railroad: the oranges, wrapped in paper and cooled with ice, reached St Louis in one month. It was an Eliza Lovell (married Tibbets) in Riverside, an early pioneer of the town, who planted seedlings of Brazilian "navel" oranges in 1873 and set a trend. People soon realized that southern California had the perfect weather for these oranges, and citrus orchards spread to Anaheim (a German colony), San Bernardino (a Mormon colony), Pasadena (an Indiana colony), Redlands (a Chicago colony), Riverside, Pomona, etc. The railway connecting Los Angeles to Chicago came at the right time. Chicago's meat-packing tycoon Gustavus Swift had invented in 1878 a refrigerated car to transport meat, but Edwin Earl, the rare native Californian, perfected it in 1890 specifically to transport oranges. The railroad had been brought to California to connect the East Coast with the gold mines, but it became truly lucrative thanks to the orange and to the agriculture in general.

The orange reflected some general trends in California's agriculture. There was a shift from large-scale grain cultivation to small-scale intensive fruit cultivation. Fruit replaced wheat as the main produce of California. It wasn't just oranges. Californian farmers indulged in experiments with genetically modified fruit. For example, in 1875 Luther Burbank settled in Santa Rosa, north of San Francisco, and started developing hundreds of new varieties of fruits. At the same time, in the 1880s California's agriculture, scarce in labor, underwent a rapid mechanization, pioneering the adoption of new machines (gang plows, large headers, combined harvesters) that had not been invented there but were increasingly built there (mostly in Stockton). In 1919 California was producing 57% of the oranges, 70% of the prunes/plums, over 80% of the grapes and figs, and virtually all of the apricots, almonds, walnuts, olives, and lemons grown in the USA. In 1920 more than 10% of California farms had tractors compared with 3.6% for the nation as a whole.

Stockton was one of the main wheat-producing regions thanks to the land reclaimed from the delta of the San Joaquin River. Benjamin Holt, who had arrived in California in 1883 and formed the Stockton Wheel Company with his two brothers, invented the steam-driven tractor in 1892 and the continuous-track tractor in 1904, which he named "Caterpillar". This machine, upgraded to the age of gasoline, would inspire the armored tank, invented by the British in 1915 during World War I.

At the 1893 Columbian Exposition in Chicago, the Southern California pavilion designed by Chamber of Commerce's superintendent Frank Wiggins (himself one of the sick who had migrated in 1886 from the Midwest and one of the lucky ones who was indeed cured by the sunny weather) was one of the most popular attractions, depicting Southern California as an Eden: an “Olive Oil Tower” from Santa Barbara ranches, a “Walnut Tower” from Los Angeles County growers, and a 12-meter tall "Tower of Oranges".

The Midwestern immigrants were not a poor, illiterate crowd of desperados like the gold diggers of the Gold Rush: they came with money, to buy land, to build a home, to open a shop. Pasadena in the north, Santa Monica to the west and Riverside to the east were ideal locations for those who were simply looking for a piece of land to build a dream home, while Los Angeles itself appealed to those who wanted to start a farm, thanks to a growing reputation as the perfect combination of soil and climate. For example, in 1887 Frederick Rindge and his wife May moved from Boston to Santa Monica and in 1892 bought the nearby ranch of Malibu (technically speaking, the land grant Rancho Topanga Malibu Sequit) for a small sum of money, at a time when there were no roads to Malibu, for the purpose of building their dream country home, modeled after the villas of the Italian and French rivieras (today Malibu is one of the most expensive places in the world). In 1887 Amos Throop, a Chicago anti-slavery politician, retired to Pasadena and four years later founded Throop University (renamed California Institute of Technology, aka CalTech, in 1920). The writer Edgar Rice Burroughs, who had gotten rich thanks to a series of stories started with "Tarzan of the Apes" (1912), moved to southern California in 1919, purchasing a piece of land in San Fernando Valley from Harrison Gray which he renamed Tarzana Ranch, thus jumpstarting today's Tarzana town.

In 1869 two recent immigrants, Isaac Lankershim (from Missouri) and Isaac Van Nuys (from upstate New York), purchased the ranch that used to belong to the Mission San Fernando from Pio Pico (who needed money to build his hotel in Los Angeles, while Pio's brother Andres, the old Mexican commander, continued to live in the mission itself as in a palace). Their farming and ranching venture was so successful that in 1876 two cargo vessels carried their wheat from San Pedro Harbor to Liverpool in England, the first grain ever shipped from California to Europe. After Lankershim died, Van Nuys (married to his daughter) came to own the entire southern portion of the San Fernando Valley. In 1888 Lankershim’s son James carved out a town that would become North Hollywood, and in 1909 a syndicate comprising Moses Sherman and Harry Chandler purchased Van Nuys' ranch and founded the town of Van Nuys in 1911. Peter Janss, a Danish-born physician who had originally moved to Los Angeles in 1893 to practice medicine but had quickly became a real-estate developer, developed Belvedere Heights in 1905 (now part of East Los Angeles) and in 1909 founded the town of Yorba Linda in Orange County. Janss' company was chosen to develop Van Nuys.

In 1904 the visionary Chicago astronomer George Ellery Hale, who a decade earlier had built the world's largest telescope in Wisconsin, picked Mount Wilson as the site for a new astronomical observatory and moved to nearby Pasadena. In 1907 Hale joined the renamed Throop Polytechnic Institute and turned it into a scientific and engineering school, all the while building the new largest telescope (1908). He would later beat his own record twice more: at Mount Wilson again in 1917 (the largest telescope for 22 years) and finally at Palomar near San Diego in 1949 (the largest for 26 years).

On New Year's Day in 1890, Pasadena held its first "Rose Parade", conceived and publicized by wealthy immigrants like Charles Frederick Holder (a naturalist who had arrived from New York in 1885) to promote the region: while the Midwest and the Northeast were buried under snow, Pasadena was celebrating the New Year in mild weather. Within a few years many newspapers in other states were covering the event.

Immigrants from the Midwest quickly outnumbered the original rancheros, and immigrants form the East Coast turned some ranches into towns.

The vast amount of free land was the equivalent of the gold mines of 1849, except that it was much easier to "discover" and monetize. It was Los Angeles's gold rush.

The first major California vineyards were established by the Catholic missions of San Gabriel and San Fernando, but not for commercial purposes at a time when nearby Los Angeles had maybe 200 people. The first commercial vineyards were created in the region, at a time when southern California was still under Mexican rule, and way before the Gold Rush. Jean Louis Vignes opened the first winery in 1833, acquired in 1855 by his nephews Jean-Louis and Pierre Sainsevain, followed by his neighbor William Wolfskill in 1841 (more famous for the Valencia oranges). When the Bay Area was overrun by 49ers in search of gold, the countryside around Los Angeles was being overrun by European immigrants venturing into vineyards, like Matthew Keller (1852), an Irishman who had lived in Mexico, and his friend and fellow Irishman Andrew Boyle (1858). In 1853 two Prussian musicians (violinist Charles Kohler and flautist John Frohling) opened a winery and then in 1857 they convinced 50 Bavarian-American families of the San Francisco area to join their Los Angeles Vineyard Society in a place that they named Anaheim. By the end of the decade there were more than 100 wineries in southern California.

In 1859 Edwin Drake had struck oil in Pennsylvania and had started an "oil rush". There were no cars and oil was not yet used for making gasoline, but kerosene quickly replaced whale oil for lighting, and that was a massive market. Oil was produced in north California already in 1865, and in 1867 Thomas Bard had started producing oil from a well in the Ojai Valley (northwest of Los Angeles), but California's oil boom started in 1892 when Edward Doheny, who was actually a silver prospector who had made money in New Mexico, and Charles Canfield discovered oil in Los Angeles.

Five years later Los Angeles was littered with 2500 wells and 200 oil companies. They quickly consolidated in a handful of companies, the biggest among them being the Union Oil Company founded in 1890 by Lyman Stewart and Wallace Hardison through a merger with Thomas Bard's company, but also Doheny's own company (which in 1916 would become the Pan American Oil Company after he had made a huge oil strike in Mexico), and also the Pacific Coast Oil Company, co-founded in 1879 in San Joaquin Valley by Lloyd Tevis (and acquired in 1900 by the Standard Oil Company of New Jersey, the future Chevron).

That was perfect timing: Drake had discarded gasoline, a by-product of oil distillation, but in 1886 Karl Benz and Gottlieb Daimler invented the gasoline-powered automobile and in 1893 the first gasoline-powered car was made in the USA (by Charles and Frank Duryea Massachusetts). 1899 is the year when car manufacturers popped up everywhere, including Ford's Detroit Autombile Company, and the year when Alexander Winton drove from Cleveland to New York taking along a reporter, thereby generating a lot of publicity and ending the trip in front of a million people. Gasoline quickly became the main reason to drill for oil. By 1903 California became the leading oil-producing state, passing Pennsylvania and Texas (that had started pumping oil in 1894, and would soon pass California thanks to the 1901 oil strikes of Beaumont, the largest of the era).

Kern County had been populated first by gold miners of the 1850s who scattered in the Sierra Nevada mountains and then by farmers of the southern states fleeing the Civil War who established cotton plantations. The town of Bakersfield had been created in 1863 as Baker's Field, the land near the Kern River acquired by Thomas Baker, a lawyer from Ohio. The early oil prospectors used gold-mining experience to mine oil and asphalt. In 1865 Josiah Lovejoy opened the Buena Vista refinery to make kerosene for lamps and lubricants for wagon wheels, and later asphalt to pave roads (in the 1890s). Like everybody else at the time, he threw away the useless liquid byproduct called "gasoline". The McKittrick oil field was discovered in 1896 but the boom started in 1899 when Jonathan Elwood and his son James discovered the Kern River oil field, northeast of Bakersfield. Overnight, tent towns were born. Within three years more than two thousand oil companies were incorporated in California. Unfortunately, overproduction in Kern County caused the price of a barrel of California crude oil to collapse (from one dollar in 1899 to 12 cents in 1904). Oil was now used also and mainly for lighting. Some celebrated discoveries added excitement to the local industry, like the Midway gusher (1909) and the Lakeview gusher (1910).

Meanwhile, Los Angeles kept expanding. In 1895 the Southern Pacific opened a branch line to Burbank, thus opening up San Fernando Valley to the Midwestern immigrants.

Los Angeles was never a mining town but a big part of its history intersects with the history of mining.

Elias Baldwin, who had made his fortune with the Ophir mines of the Comstock lode in Nevada, started buying land in southern California in 1875, in particular in the San Gabriel Valley, and opened his Santa Anita Ranch. When in 1875 the bank of William Workman and Francisco Temple went bankrupt, Baldwin acquired it as well as all the land that the Workman-Temple family still owned in both San Gabriel Valley and west of Los Angeles (Rancho La Cienega). In 1885 he managed to bring the railroad to Santa Anita Ranch and started subdividing the land. In 1903 he founded the city of Arcadia. At the peak Baldwin owned more than 160 square kilometers of land around Los Angeles.

The Los Angeles Philharmonic Orchestra was established in 1919 by the son and namesake of Montana's copper baron and senator William Andrews Clark, who was one of the richest men of his time although less famous than John Davison Rockefeller, John Pierpont Morgan and Andrew Carnegie; the tycoon who in 1905 had built the railroad from Salt Lake City to Los Angeles, thereby creating the town of Las Vegas, and who had retired in New York to a 100-room mansion. It was copper from his father's mines that was used to make the electrical wires that electrified America. The son was a collector of rare books and an amateur violinist. The Philharmonic took residence in the nine-story steel-and-concrete Trinity Auditorium, designed by Harry Deckbar in 1914 for a Methodist church.

Hubert Eaton, a former mining engineer, took over the graveyard of Tropico, north of downtown Los Angeles (and now part of Glendale), and in 1917 turned it into the first Forest Lawn Memorial Park, inspired by Renaissance parks and by landscape architect Frederick Law Olmsted. Blacks, Jews and Chinese were not admitted. Eaton opened other "cemetery-parks". The original Forest Lawn became Hollywood's equivalent of Paris' Pere-Lachaise cemetery, featuring the graves of stars such as Clark Gable, James Stewart, Mary Pickford, Humphrey Bogart and Walt Disney.

Biddy Mason, born into slavery in Georgia, was taken west by Mormons and in 1851 followed the Mormon group that traveled to Southern California under Robert Smith, settling with him in San Bernardino, still half a slave, became a nurse in Los Angeles, saved money, bought properties and became a philanthropist, founding in 1872 the First African Methodist Episcopal (FAME) Church, Los Angeles' first Black church. (A century later pastor Cecil Murray would grow FAME into a megachurch).

Southern California was now experiencing an oil boom, a tourism boom and an orange boom. And so by 1890 the population of Los Angeles had quintupled to 50,000.

As immigrants kept arriving from the Midwest and the East Coast, Los Angeles' population doubled in a decade and passed 100,000 by 1900, and then even tripled to more than 300,000 in 1910. San Francisco was still much bigger, having passed 400,000 people around 1900. Unlike multi-ethnic San Francisco, Los Angeles was a "white" city: most immigrants came from other white Anglo-Saxon cities/towns of the USA. The ethnic minorities were very small: in 1890 the Asians were 2% and the Mexicans 1% of the population. Still in 1930, out of more than one million people, there were only 70,000 Jews, 45,000 Hispanics, 30,000 Asians and 30,000 Blacks.

Ironically, the transcontinental railroad that had been conceived to link the eastern cities with the Bay Area ended up benefiting mostly Los Angeles.

Henry Huntington, nephew of Collis Huntington, one of the "Big Four" of the transcontinental railroad, applied the business model of the Pico Street electric line on a bigger scale: he established both the Huntington Land and Improvement Company (a real-estate firm to purchase, subdivide and resell land, notably in the San Gabriel Valley) and the Pacific Electric rail network, which, starting in 1901, spread to many suburbs (2,000 kms) thanks to an army of Mexican immigrant laborers. His business partner was banker Isaias Hellman. Huntington had already acquired control of LACE, now renamed Los Angeles Railway or LARy, in 1898: LARy ran yellow cars, Pacific Electric operated red cars. He even founded an electric company, the Pacific Light and Power Corporation, initially to provide electricity for his trolley cars but then also to supply electricity to the homes of Los Angeles and the San Gabriel Valley. Huntington got rich selling land: the railway was just a means to get people to buy land in the suburbs that he connected with downtown Los Angeles. Thanks to the interlocking success of his business triangle, Huntington became one of the region's largest employers and expanded into agriculture and hospitality. Huntington was the main force behind the dramatic acceleration of urban development in the Los Angeles area. His great invention was the detached, single-family home located in the suburbs of one of the most modern cities in the country. That was the great compromise that turned the Californian lifestyle into a national dream. While emigrants headed to the big modern cities usually lost the idyllic natural environment and vast domestic spaces of their rural hometowns, and had to accept the confined space of an apartment in a crowded block, those who emigrated to Huntington's suburbs found the best of both worlds: a house with a garden (both in the front and in the back) and equipped with the comforts of modern life (i.e. electricity). Incidentally, in 1913 he married his uncle's widow Arabella, who had inherited the fortune of her husband, and, when he died in 1924, she inherited his fortune too. Arabella became the richest woman in the USA.

Hellman was involved in many of these schemes and his influence extended to San Francisco: after fellow banker Edward Harriman purchased the Southern Pacific Railroad in 1901 and gained control of Wells Fargo, Hellman engineered a merger with the Nevada Bank to form San Francisco's biggest bank, the Wells Fargo Nevada National Bank (1905). Hellman was also crucial in restoring financial faith in San Francisco after the earthquake, and in financing the 1915 Panama-Pacific International Exhibition.

In 1893 a scenic railway opened to link Pasadena and Oak Mountain in the San Gabriel Mountains, built by David Macpherson, a Canadian civil engineer who had worked on the just completed railroad from Ciudad Juarez to Mexico City (1884) and had moved to Pasadena for health reasons in 1885. It was backed by Thaddeus Lowe, a millionaire inventor, aeronaut and banker who had moved to Los Angeles in 1887 and in 1890 had retired to his new three-story Victorian mansion in Pasadena, for whom the mountain was renamed Mount Lowe. The railway included the 1,000-meter "Great Incline" of an extremely steep gradient. In 1894 Lowe opened a white hotel at the top, the Echo Mountain House. Huntington acquired the railway in 1902 and marketed the white hotel as a tourist attraction.

Los Angeles differed from San Francisco and from most other cities in that the urban railways were private enterprises, created by wealthy individuals. Instead of expanding slowly from downtown, Los Angeles expanded by leaps and bounds in the suburbs.

The car, better known as "horseless carriage", was still a mirage. Nonetheless in 1900 Los Angeles already had the Automobile Club of Southern California, whose members were mainly rich people. The biggest obstacle to the spread of the automobile was the poor condition of the roads, designed for horses, mules and wagons. In 1906 the Automobile Club began posting road signs. 1908 is the watershed year when Henry Ford introduced the Model-T automobile, and the whole country started dreaming of owning a car. Finally, in 1910 the state of California funded a Highway Act to improve the roads, and in 1916 the Federal Road Act would further accelerate the paving of the roads.

The rapidly expanding city, located in an arid region, needed water. The Irish-born self-taught water engineer William Mulholland, a 15-year-old runaway when he had arrived in America in 1877, managed the construction of the Los Angeles Aqueduct (1904–13) that brought water from the Owens Valley, 400 kilometers away. It was built by about 4,000 laborers through the Mojave Desert and required gangster-style techniques to convince the ranchers of Owens Valley (1,167 of them) to sell their land to the city of Los Angeles. At 375 kms, it was the longest aqueduct in the world. It was running through 142 tunnels and countless bridges. Construction required 200 kms of railway and 800 kms of roads to bring supplies to the 4,000 workers. It was bringing more water than Los Angeles needed and so it was also used to turn the barren San Fernando Valley (like Burbank) into a land of citrus groves and tract homes. After more water was diverted by Los Angeles in 1926-27, the Owens River was all but drained and Owens Valley was reduced to a dust bowl. The townsfolk of Owens Valley were so resentful that they often resorted to bombing sections of the aqueduct. The San Francisquito Dam north of Los Angeles collapsed in 1928, just two years after completion, releasing a surging wall of water that drowned 400 people. The disaster ended Mulholland's career.

In this western paradise, workers were brutally exploited and denied the opportunity of organizing themselves into labor unions. In 1910 Harrison Gray Otis, the publisher of the Los Angeles Times who had published anti-labor articles, became a target of socialist terrorists who in 1910 bombed the the newspaper's offices, killing 20 employees.

A second Chinatown was growing in Los Angeles. Chinese and Japanese merchants funded the establishment of a new farmers' market in 1909, the City Market. Chinese merchants and workers quickly took over the neighborhood, which became known as Market Chinatown. It was a cosmopolitan Chinatown because Japanese, Italians and other ethnic groups involved in wholesale produce moved there. All sorts of food industries popped up, including David Jung's Hong Kong Noodle Company which in 1918 invented the "fortune cookie". Clearly this was not the Chinatown of opium dens and tong wars.