Placerville (/ˈplæsərvɪl/, PLASS-ər-vil; placer, Spanish for "sand deposit", representing the placer mining that was predominant in the town's development, and ville, French for "town") is a city in and the county seat of El Dorado County, California, United States. The population was 10,747 as of the 2020 census, up from 10,389 as of the 2010 census. It is part of the Sacramento metropolitan area.

A former Maidu settlement called Indak was located at the site of the town.

After the discovery of gold at Sutter's Mill in nearby Coloma, California, by James W. Marshall in 1848 sparked the California Gold Rush, the small town now known as Placerville was known as Dry Diggin's after the manner in which the miners moved cartloads of dry soil to run water to separate the gold from the soil.

Later in 1849, the town earned its most common historical name, Hangtown, because of the numerous hangings that had occurred there. However, there is debate on exactly how many lynchings occurred in the town. The town had no police force (in 1849) and five immigrants attempted robbery of a Mexican gambler. Of the five immigrants, two Frenchmen and one Chilean were known wanted men, and they were not given any trial, instead they were hanged on an oak tree on Main Street by a mob. The name "Hangtown" stuck after that event.

By about 1850, the temperance league and a few local churches had begun to request that a more friendly name be bestowed upon the town. The name was not changed until 1854 when the City of Placerville was incorporated, taking the name from the local placer gold deposits. At its incorporation, Placerville was the third largest town in California. In 1857, the county seat was then moved from Coloma to Placerville, where it remains today. The town's first post office opened in 1850. In 1871, the Placerville Union Cemetery was founded by a group of fraternal organizations, and it holds the graves of many of the city founders.

Placerville was a central hub for the Mother Lode region's mining operations. The town had many services, including transportation (of people and goods), lodging, banking, and had a market and general store. The history of hard-rock mining is evidenced by an open and accessible Gold Bug Park & Mine, now a museum with tours and books.

The Sacramento and Placerville Railroad, (later part of the Southern Pacific Railroad) had a branch line that extended from Folsom to Placerville. The track was abandoned in the 1980s and is now used by heritage railroads. The Camino, Placerville and Lake Tahoe Railroad (now abandoned) also operated an eight-mile (thirteen-kilometer) shortline that operated between Camino, California, and Placerville until June 17, 1986. The track right-of-way is now a 37-mile hiking and biking path that connects the city of Folsom, California to the town of Camino with plans to extend the trail across the entire El Dorado county and eventually to Lake Tahoe.

Placerville is now registered as California Historical Landmark #701.