Colo is a city in Story County, Iowa, United States. The population was 868 at the 2000 census. It is part of the 'Ames, Iowa Metropolitan Statistical Area', which is a part of the larger 'Ames-Boone, Iowa Combined Statistical Area'. Colo is located at the intersection of the historic Lincoln Highway and the Jefferson Highway. The intersection is marked by the historic complex of Reed/Niland Corner, which includes a museum/diner, vintage gas station, and small park. For modern-day travelers, Colo lies at the intersection of U.S. Highway 30 and U.S. Highway 65. Colo lies also along the cross country line of the Union Pacific railroad. Colo's most popular attraction is Hickory Grove Park, Story County's largest recreational, fishing, and swimming area (445 acres, dominated by a 98-acre lake). Just east of town, along the Lincoln Highway, lies Colo Marsh, which drains into the Iowa River just east of Marshalltown.