The mining camp of Mariposa materialized in the spring of 1849 when a miner named Alex Godey found a few flakes of gold while prospecting the streams of Colonel Frémont’s Las Mariposas Grant. Gold was plentiful in the vicinity and it wasn’t long before a good number of miners were settled in along the small flat bordering Mariposa Creek, a little ways below the present Hwy 140 bridge. Later that fall, Palmer, Cook & Co. sent about fifty men from San Francisco to work a claim they had leased from John Charles Frémont, which later became the Mariposa Mine. Their arrival soon led to a townsite being laid out, and Mariposa took its first step towards permanency.

In addition to the rich placers of the area, the camp chanced to be located on the gold-bearing quartz veins of the Mother Lode. Its future thus insured, the small mining town grew in size and importance as miners from the surrounding areas gravitated to the rich diggings. Saloons, general stores, restaurants, and hotels were quickly established to take care of the miners’ every need.