A whaling ship captain named William Richardson came ashore in 1835 and set up a tent at what is now the 800 block of Grant Avenue. The first survey was in 1839 and the streets were given their English names at that time.
On July 9, 1846, Captain John Montgomery came ashore with 70 troops and read a proclamation claiming the territory for the United States. They took down the Mexican flag and replaced it with the Stars and Stripes. There was no resistance. When Sam Brannan arrived later that month with a group of 238 other people, they almost doubled the size of the city.
Yerba Buena officially became San Francisco in 1847 when the Spanish alcalde, or mayor, decided to change the name for easy identification with the bay.
On May 12, 1848, Sam Brannan stood in Portsmouth Square and announced that gold had been found in the Sierras, setting off the largest peacetime migration in United States history. By 1851, the population had boomed to 25,000 people, most of them bachelors, and there were 500 bars.
In the 1840s and 1850s, China was an inhospitable place to live. To escape the floods, droughts, rebellion and civil war, many Chinese who had heard of the "Golden Mountains" in California left China to seek their fortunes. Thousands of Chinese, most of them from the Guangdong Province in southern China, made their way to the gold fields. They met with suspicion and prejudice from other miners and many of them soon came back to San Francisco where jobs could be found and a familiar culture had taken root.
Like many other immigrant groups, the Chinese met with suspicion and envy from the "natives". Oppressive laws were passed that limited the jobs they could have, assessed exorbitant license fees on the ones they could work in and excluded them from giving testimony in court against a white man. Some of these laws persisted until World War II.
After the earthquake and fire of 1906, when all the birth records were burned, many Chinese were able to get citizenship by claiming they were born here. The fire also destroyed the rickety wood tenements that existed at the time. The new buildings you see today are American architects' ideas of what Chinese buildings should look like.