The Calaveras Skull (also known as The Pliocene Skull) was a human skull found by miners in Calaveras County, California, which was purported to prove that humans were in North America as early as the Pliocene, and used to support the idea the humans, mastodons, and mammoths had coexisted. It was later revealed to be a hoax, although it is now known that humans, mastodons, and mammoths had indeed coexisted, but much more recently (the Pleistocene). Coincidentally, calaveras is the Spanish word for "skulls".



Calaveras County ( (listen)), officially the County of Calaveras, is a county in the northern part of the U.S. state of California. As of the 2010 census, the population was 45,292. The county seat is San Andreas. Angels Camp is the county's only incorporated city. Calaveras is Spanish for "skulls"; the county was reportedly named for the remains of Native Americans discovered by the Spanish explorer Captain Gabriel Moraga.

Calaveras County is in both the Gold Country and High Sierra regions.

Calaveras Big Trees State Park, a preserve of giant sequoia trees, is in the county several miles east of the town of Arnold on State Highway 4. Credit for the discovery of giant sequoias there is given to Augustus T. Dowd, a trapper who made the discovery in 1852 while tracking a bear. When the bark from the "Discovery Tree" was removed and taken on tour around the world, the trees became a worldwide sensation and one of the county's first tourist attractions. The uncommon gold telluride mineral calaverite was discovered in the county in 1861 and is named for it.

Mark Twain set his story "The Celebrated Jumping Frog of Calaveras County" in the county. The county hosts an annual fair and Jumping Frog Jubilee, featuring a frog-jumping contest, to celebrate the association with Twain's story. Each year's winner is commemorated with a brass plaque mounted in the sidewalk of downtown Historic Angels Camp and this feature is known as the Frog Hop of Fame.

In 2015, Calaveras County had the highest rate of suicide deaths in the United States, with 49.1 per 100,000 people.