Grass Valley is a city in Nevada County, California, United States. As of the 2010 United States Census, its population was 12,860. Situated at roughly in elevation in the western foothills of the Sierra Nevada mountain range, this northern Gold Country city is by car from Sacramento and west of Reno.
Grass Valley, which was originally known as Boston Ravine and later named Centerville, dates from the California Gold Rush, as does nearby Nevada City. Gold was discovered at Gold Hill in October 1850 and population grew around the mine. When a post office was established in 1851, it was renamed Grass Valley the next year for unknown reasons. The town was incorporated in 1860.
The essential history of Grass Valley mining belongs to the North Star, Empire and Idaho-Maryland mines, for continuous production over a span of years. From 1868 until 1900, the Idaho-Maryland mine was the most productive in the district. From 1900 until 1925, the North Star and the Empi