Liberty Township, one of thirteen townships in Butler County, Ohio, United States, is in the east-central part of the county, just south of the city of Monroe. With an area of about 29 square miles (75 km2) it is smallest of the thirteen townships but one of the fastest growing areas in southwest Ohio, having a population of 37,259 at the 2010 census, up from 22,819 in 2000 and just 9,249 in 1990. It was named for Liberty, Pennsylvania, at the suggestion of John Morrow, a resident in the township at the time of its formation in 1803 who was the brother of Ohio Governor Jeremiah Morrow, after his hometown. The first settler was John Nelson, who arrived in 1796, seven years before Ohio became a state. It is one of 25 Liberty Townships statewide.