As the city's name suggest its geography is dominated by a high ridge separating the valleys of the Big and Little Cottonwood Creeks. At the eastern edge of the city, these valleys narrow into the Big and Little Cottonwood Canyons within the Wasatch Mountains, respectively; this is reflected by the city's official nickname, "City between the canyons". The ridge is covered in suburban housing, but most commercial development has been restricted to the lower-lying areas north of the ridge (along Fort Union Boulevard, in Fort Union itself, and near Big Cottonwood Creek and the "Old Mill" in the northeast corner of the city).