In 1847, John Fremont paid $3,000 ($98,000 in 2021) for 70 square miles in the Sierra foothills, near Yosemite (California's non-Native American population was approximately 14,000 in 1848, therefore did not have a great demand for land). The previous owner had purchased the land on a "floating grant," and the property boundaries were not precisely fixed. Fremont's mining problems arose because it was difficult to figure if his mines were on his own property or on public land; additionally, squatters moved onto his land looking for gold. The Supreme Court eventually ruled in Fremont's favor in 1856.
The Mariposa War (December 1850-June 1851) was a conflict between Native Americans and miners in Mariposa County, CA. The gold miners pushed the Indians off their land, and the Government forced them onto reservations.