No, Black Hawk, Colorado is not an Indian reservation. Black Hawk is a historic mining town located in Gilpin County, Colorado. It is known for its rich history in gold mining and its modern-day casinos. The town is part of the Denver-Aurora-Lakewood, CO Metropolitan Statistical Area and is governed by local municipal authorities, not by any Native American tribe.
Indian reservations are areas of land managed by a Native American tribe under the U.S. Bureau of Indian Affairs. These reservations are sovereign entities with their own governance structures. Black Hawk, being a municipality, does not fall under this category.