Austinville is an unincorporated community in southwestern Butler County, Iowa, United States. It lies along Iowa Highway 57 southwest of the city of Allison, the county seat of Butler County. Although Austinville is unincorporated, it has a post office with the ZIP code of 50608, which opened on 3 October 1892. As of the United States Census, 2020, the ZIP code's population was 38.