Alturas (formerly Dorris Bridge, Dorris' Bridge, and Dorrisville) is the county seat of Modoc County, California. Alturas is still referred to as Kasalektawi by the Achomawi (Pit River Tribe) Indigenous First Peoples. The population of Alturas was 2,827 at the 2010 census.
Alturas is located at the confluence of the south and north fork of the Pit River, east of the center of Modoc County, at an elevation of 4,370 feet (1,332 meters). As the county seat, the town is a home to regional government offices, including a California Highway Patrol office and a state Department of Motor Vehicles office.
Alturas occupies what was initially an Achumawi (Pit River) village known as Kosealekte or Kasalektawi. The city was initially known as Dorris Bridge or Dorris' Bridge, named after Pressley and James Dorris, who built a bridge across the Pit River at this location.
The Dorris Bridge post office opened in 1871. The town was renamed Dorrisville in 1874 and Alturas in 1876, the latter meaning "heights" in Spanish. The census of 1880 showed a population of 148. However, settlement continued over the next two decades, until the city was incorporated on September 16, 1901.