Brigham City is a city in Box Elder County, Utah, United States. The population was 17,411 at the 2000 census. By 2004 its estimated population had decreased slightly to 17,149. It is the county seat of Box Elder County^GR6. It lies on the western slope of the Wellsville Mountains, a branch of the Wasatch Range at the western terminus of Box Elder Canyon. Brigham City saw most of its growth during the 1950s and 1960s, but has seen a struggling economy and stagnating growth since then. It is currently the headquarters of Thiokol, the company that created the solid rocket boosters for the Space Shuttle.