St. Maries is a city located in Benewah County, Idaho. St. Maries has a 2026 population of 2,487. It is also the county seat of Benewah County. St. Maries is currently growing at a rate of 0.36% annually and its population has increased by 5.16% since the most recent census, which recorded a population of 2,365 in 2020.