The town was founded as a mining camp on the banks of a seasonal stream known as Aqua Fria.
This original town site was located about 6.0 miles (9.7 km) to the west of present-day Mariposa.
Prior to this, Southern Sierra Miwuk resided in the area.
After a flood during the winter of 1849/50, and fires, the town was moved to the location of today's Mariposa, although mainly due to better terrain and the presence of Mariposa creek, a large producer of placer gold.
The gold in small Aqua Fria creek was soon removed, and lacked water most of the year.
So the populace moved on to the new boomtown.
The large Mariposa mine soon opened, with a 40-foot waterwheel crushing gold ore.
This provided a stable source of employment, and Mariposa soon became the supply hub for hundreds of outlying mining districts.
Placer gold, that which is found in creekbeds and alluvial deposits, was soon extinguished, and the era of hard rock, deep mining began.
In 1851 the "new" town of Mariposa became the county seat of the county of Mariposa, which reached nearly to Los Angeles.
By 1854 Mariposa had a grand courthouse which is still in operation.
 Some refer to the lumber being cut from an area to the east of town known as "logtown" but no maps or certifiable sources can attest to the existence of Logtown.
Most likely the lumber for the courthouse was milled in Midpines, where there was an unusual abundance of sugar pine trees.

John C. Frémont had a Spanish land grant that gave him ownership of most of the Mariposa mining district, but the possibility of securing his property was nearly impossible due to the huge influx of gold seekers, and little or no enforcement from the few law keepers available.
In book #1 of Mariposa county records, originally filed in Aqua Fria, on Page 2, there is a claim known as the Spencer quartz mine and adjacent millsite.
 This claim was just hundreds of feet from Fremonts grant line, and its owners were Lafayette H. Bunnell, and Champlain Spencer, who became rather wealthy from the placer gold in Whitlock and Sherlocks creek.
They later erected a 40' waterwheel and steam mill, along with several arrastras.
 Mr. Bunnell later published a memoir of his time in Midpines and entry to Yosemite valley, which is still in print today - "The Discovery of the Yosemite".
 Mr. Spencer has never been acknowledged as having named Half Dome, a prominent feature in Yosemite valley.
These educated gentlemen and adventurers eventually sold "Spencers Mill" to a French and English conglomerate for a tidy sum.
 All is quiet now on Spencers mill, but much evidence of a series of mills and the arrastras remain.

The US Army built the Mariposa Auxiliary Field (1942-1945) to train World War 2 pilots, after the war the airfield became the current Mariposa-Yosemite Airport.

On July 18, 2017, a fast-moving wildfire, the "Detwiler Fire", forced the evacuation of the entire town.
The town was founded as a mining camp on the banks of a seasonal stream known as Aqua Fria. This original town site was located about 6.0 miles (9.7 km) to the west of present-day Mariposa. Prior to this, Southern Sierra Miwuk resided in the area. After a flood during the winter of 1849/50, and fires, the town was moved to the location of today's Mariposa, although mainly due to better terrain and the presence of Mariposa creek, a large producer of placer gold. The gold in small Aqua Fria creek was soon removed, and lacked water most of the year. So the populace moved on to the new boomtown. The large Mariposa mine soon opened, with a 40-foot waterwheel crushing gold ore. This provided a stable source of employment, and Mariposa soon became the supply hub for hundreds of outlying mining districts. Placer gold, that which is found in creekbeds and alluvial deposits, was soon extinguished, and the era of hard rock, deep mining began. In 1851 the "new" town of Mariposa became the county seat of the county of Mariposa, which reached nearly to Los Angeles. By 1854 Mariposa had a grand courthouse which is still in operation.  Some refer to the lumber being cut from an area to the east of town known as "logtown" but no maps or certifiable sources can attest to the existence of Logtown. Most likely the lumber for the courthouse was milled in Midpines, where there was an unusual abundance of sugar pine trees.
John C. Frémont had a Spanish land grant that gave him ownership of most of the Mariposa mining district, but the possibility of securing his property was nearly impossible due to the huge influx of gold seekers, and little or no enforcement from the few law keepers available. In book #1 of Mariposa county records, originally filed in Aqua Fria, on Page 2, there is a claim known as the Spencer quartz mine and adjacent millsite.  This claim was just hundreds of feet from Fremonts grant line, and its owners were Lafayette H. Bunnell, and Champlain Spencer, who became rather wealthy from the placer gold in Whitlock and Sherlocks creek. They later erected a 40' waterwheel and steam mill, along with several arrastras.  Mr. Bunnell later published a memoir of his time in Midpines and entry to Yosemite valley, which is still in print today - "The Discovery of the Yosemite".  Mr. Spencer has never been acknowledged as having named Half Dome, a prominent feature in Yosemite valley. These educated gentlemen and adventurers eventually sold "Spencers Mill" to a French and English conglomerate for a tidy sum.  All is quiet now on Spencers mill, but much evidence of a series of mills and the arrastras remain.
The US Army built the Mariposa Auxiliary Field (1942-1945) to train World War 2 pilots, after the war the airfield became the current Mariposa-Yosemite Airport.
On July 18, 2017, a fast-moving wildfire, the "Detwiler Fire", forced the evacuation of the entire town.
Mariposa, California