Onondaga Hill was the location of the first Onondaga county courthouse, built in 1805 and in use as a school after the county seat moved to Syracuse in 1830. Until 2005, the hamlet was the location of Onondaga's town hall. The Onondaga Free Library and the Town of Onondaga Historical Society are in Onondaga Hill. Community General Hospital and Van Duyn Home and Hospital are located on the eastern edge of the hamlet, near the Syracuse city line. The main campus of Onondaga Community College lies on the hamlet's western edge. Onondaga Hill is populated mainly of middle-class families. The children of Onondaga Hill attend the Westhill Central School District.