During the Gold Rush Tuolumne County was arguably the heartland of the Southern Mines.
One of the original 27 counties (1850), Tuolumne has always had Sonora as her county
seat. The major mining area occupied a huge basalt mesa, Table Mountain, that stretches
some thirty miles along the Stanislaus River. Close to the northern end lies COLUMBIA,
best preserved and most thoroughly restored of the southern mining towns. Near it is
SONORA and four miles south lies JAMESTOWN. On the Tuolumne River are located CHINESE
CAMP, JACKSONVILLE and BIG OAK FLAT.