Moore's Flat was a historic mining town located on the San Juan Ridge about 19 miles northeast of Nevada City, California and about 5 miles northeast of North Bloomfield, California.

By 1852, the town reportedly had about 500 residents, several stores, three hotels and "a large number of saloons.

[9] Toll roads provided improved access to Nevada City and the Ridge communities.

[10] An enterprising stable owner established a branch in Nevada City and offered customers the option of renting a horse, dropping it off at the Nevada City branch while visiting there for a few days and then bringing the horse back to Moore's Flat, all for three dollars.

In early 1865, reacting to an attempt by mine owners to reduce the wages of $3.50 or $4 a day by 50 cents, the miners organized the Moore's Flat Working-men's Protective Society.

One newspaper observed that: "There have been at Moore’s and Woolsey’s Flats a great many accidents, recently, among miners and most of them have proved fatal.

"[22] In part, this was because the gold lay under very deep gravel causing the miners to cut steep banks which produced frequent cave-ins.

Wrote an observer: "If any one wants to see a town sliding down hill, they can do so by going to Moore's Flat.

The mines in the vicinity have washed close up to the town, and the banks are continually caving.

Many of the houses have been moved to a place this side of the old town, which the residents call Jerico.

"[24] Hydraulic mining produced a lot of debris in the form of gravel and dirt that washed into the Yuba River.

Eventually, this debris and the sludge that came with, called slickens, interfered with farming in the Sacramento Valley.

1881, the Miners Union announced a boycott of Marysville and any other town trying to stop hydraulic mining.

They explained: "This Union is made up of 203 intelligent, industrious and sober men, most of them having large families to support.

They recognize that the permanent stoppage of hydraulic mining means nothing more nor less than the ruination of a large portion of Nevada county that is now thickly populated and prosperous,..."[25] Finally, in 1884, Judge Lorenzo Sawyer ruled that the mines were creating a nuisance and ordered them to stop discharging their debris into the Yuba River or its tributaries.

In 1896, a paper reported that: "Moore's Flat, although dead for a number of years, has at last come to the front.

During the winter months, there were times when the town was so snowbound that mail had to be delivered by sled or by snowshoes.

[32] While fires were common in mining towns, Moore's Flat seems to have had more than its fair share.

In January 1863, a fire which originated in the Franco American Restaurant, burned the Eagle Brewery, Justice (of the Peace) Stanley's office, and two adjoining buildings.

[36] In October 1870, a fire destroyed much of the rebuilt town, including the Masonic Hall and Marks & Co's bank.

"[45] The town had its own school house, described thusly: "The building is very old and badly out of repair, but the inside is comfortably furnished.

[58] The mine owned by Wau Yen reportedly cost $70,000 and employed about 100 miners.

In 1924, it was described as follows: "Moore's Flat, from a town of three hotels, a bank and three stores, in 1890, has dwindled until it is but a name, there being at the present time only one family living in Moore’s Flat proper“[61] Today, there is nothing readily visible of the town, except lots of rockpiles, some old mining equipment and the historic cemetery.