Denison is a city in Grayson County, Texas, United States, 1 mile (1.6 km) south of the Texas–Oklahoma border. Its population was 24,479 at the 2020 census, up from 22,682 at the 2010 census. Denison is part of the Texoma region and is one of two principal cities in the Sherman–Denison metropolitan statistical area and is also part of the Dallas-Fort Worth combined statistical area. It is the birthplace of 34th U.S. president Dwight D. Eisenhower.