Ursa is a village in Adams County, Illinois, United States. The population was 609 at the 2020 census. It is part of the Quincy, IL–MO Micropolitan Statistical Area.

Adams County is the westernmost county in the U.S. state of Illinois. As of the 2020 census, the population was 65,737. Its county seat is Quincy. Adams County is part of the Quincy, IL–MO Micropolitan Statistical Area.