Woodruff is a census-designated place in the Town of Woodruff in Oneida County, Wisconsin, United States. Woodruff is located at the junction of U.S. Route 51, Wisconsin Highway 70, and Wisconsin Highway 47 22.5 miles northwest of Rhinelander. Woodruff has a post office with ZIP code 54568. As of the 2010 census, its population is 966. Woodruff has a …Woodruff is a census-designated place in the Town of Woodruff in Oneida County, Wisconsin, United States. Woodruff is located at the junction of U.S. Route 51, Wisconsin Highway 70, and Wisconsin Highway 47 22.5 miles northwest of Rhinelander. Woodruff has a post office with ZIP code 54568. As of the 2010 census, its population is 966. Woodruff has a hospital, the Howard Young Medical Center.