Foresthill is a census-designated place (CDP) in Placer County, California, United States.

The height of mining activity in Foresthill began in 1853 after a winter landslide at the head of Jenny Lind Canyon exposed numerous nuggets of gold.

The Jenny Lind mine produced about $2,500 of gold a day for a while, up to a total output over $1 million by 1880.

The combined production of all the mines in the Forest Hill area was estimated at $10 million by 1868[5] with gold selling for $16 an ounce.

By 1880, Foresthill was one of the largest towns in Placer County, with an 80-foot (24 m) wide main street.

According to the United States Census Bureau Foresthill has a total area of 11.2 square miles (29 km2), all of it land.

There were 681 housing units at an average density of 60.9 per square mile (23.5/km2), of which 407 (65.1%) were owner-occupied, and 218 (34.9%) were occupied by renters.