Wyoming () is a state in the Mountain West region of the United States. The 10th largest state by area, it is also the least populous and least densely populated state in the contiguous United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to the south. The state population was estimated at 578,759 in 2019. The state capital and the most populous city is Cheyenne, which had an estimated population of 63,957 in 2018.