[1] The community was established to support the mine, which mainly extracted mercury, since cinnabar was abundant in the local rock formations.

[5] The New Idria Mining Company was formed soon after the discovery of cinnabar (quicksilver ore) in the southern Diablo Range of central California in 1854.

In an 1871 report to the United States House of Representatives, the surveyor general of California, Sherman Day, noted "...that the country about the mine is a series of rough and precipitous mountains and hills, intersected by deep canons; that the greater portion of it is barren and unsuited for agricultural purposes; it is essentially a minieral region..."[8] On May 30, 1974, the town and surrounding 2,000 acres were auctioned by Wershow Auctioneers, in So.

[5] The United States Postal Service operated a post office, going by the name Idria, with the ZIP Code 95027.

[10] New Idria is a California Historical Landmark (#324)[2][5] and home of the world's first Gould Rotary Furnace, which revolutionized ore processing technology worldwide.

[12] In 2011, New Idria was re-listed as a U.S. Environmental Protection Agency (EPA) Superfund site, owing to unchecked mercury run-off and contamination.

[13] As of June, 2012, the entire section of the former town site on the south side of New Idria/Clear Creek road is fenced-off.

The New Idria Mining District is known for its abundance of rare minerals such as benitoite, named after the San Benito River.