Chaska is a city in Carver County, Minnesota, United States. It is the county seat of Carver County. In 1851, the Treaty of Traverse des Sioux officially opened Little Rapids, as Chaska was then known, to settlement. Soon after, speculators moved into the new territory. Among the earliest was Thomas Andrew Holmes who, in August 1851, claimed a 20-acre (81,000 square kilometer) clearing as the Chaska townsite.