The American West is a region encompassing the western United States, consisting of the states of Washington, Oregon, California, Idaho, Nevada, Utah, Arizona, Montana, Wyoming, Colorado, and New Mexico on the American mainland and the non-contiguous states of Alaska and Hawaii; during the 19th and early 20th centuries, the West was also thought to have included Texas, Oklahoma, Kansas, Nebraska, South Dakota, and North Dakota (most lands west of the Mississippi River were called "the West" during the 1800s). In 2010, the region had a population of 74,254,423 people, with most of them living along the coast.