Onsted is a village within Lenawee County in the U.S. state of Michigan. The village had a population of 988 at the 2020 census. Located within the Irish Hills region, the village is part of Cambridge Township.

Lenawee County is a county located in the U.S. state of Michigan. As of the 2020 United States Census, the population was 99,423. The county seat is Adrian. The county was created in 1822, from territory partitioned from Monroe County. Its governing structure was organized in 1826.