Stockton is a city and the county seat of San Joaquin County in the Central Valley of the U.S. state of California. Stockton was founded by Carlos Maria Weber in 1849 after he acquired Rancho Campo de los Franceses. The city is named after Robert F. Stockton, and it was the first community in California to have a name not of Spanish or Native American origin. The city is located on the San Joaquin River in the northern San Joaquin Valley and had an estimated population of 312,697 by the California Department of Finance for 2019. Stockton is the 13th largest city in California and the 62nd largest city in the United States. It was named an All-America City in 1999, 2004, 2015 and again in 2017. Built during the California Gold Rush, Stockton's seaport serves as a gateway to the Central Valley and beyond. It provided easy access for trade and transportation to the southern gold mines. The University of the Pacific (UOP), chartered in 1851, is the oldest university in California, and has been located in Stockton since 1923. In 2012 Stockton filed for what was then the largest municipal bankruptcy in US history, which had multiple causes including financial mismanagement in the 1990s, generous fringe benefits to unionized city employees, and the 2008 financial crisis. Stockton successfully exited bankruptcy in February 2015.

Amador County, is a county in the U.S. state of California, in the Sierra Nevada. As of the 2010 census, the population was 38,091. The county seat is Jackson. Amador County, located within California's Gold Country, is known as "The Heart of the Mother Lode". There is a substantial viticultural industry in the county.

Calaveras County, 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 40,171. 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.