Campbell County is a county in the state of Wyoming, United States. According to the 2020 U.S. Census, the county had a population of 47,026. The county seat is Gillette. The lowest point in the county is at 3,400 feet above sea level at the Little Powder River in the north of the county. The highest point is 6,060 feet and is located at the summit of North Pumpkin Butte on the western border.