Glenmoor is an unincorporated community and census-designated place in southwestern St. Clair Township, Columbiana County, Ohio, United States. The population was 1,829 at the 2020 census. Glenmoor is located in southeastern Columbiana County in the southwest corner of St. Clair Township. Its northeast border is formed by U.S. Route 30, across w…Glenmoor is an unincorporated community and census-designated place in southwestern St. Clair Township, Columbiana County, Ohio, United States. The population was 1,829 at the 2020 census. Glenmoor is located in southeastern Columbiana County in the southwest corner of St. Clair Township. Its northeast border is formed by U.S. Route 30, across which is the CDP of Calcutta. It is bordered to the south by La Croft in Liverpool Township and to the west by Madison Township. The city of East Liverpool on the Ohio River is 4 miles to the southeast.