According to National Geographic, California is located in the Western region of the United States. This region also includes Colorado, Utah, Nevada, Wyoming, Montana, Oregon, Idaho and Washington.
When the Western region of the United States is broken down even further, California falls into the Pacific region of the country. The Pacific states are those that are located on the coast of the Pacific Ocean, including Alaska, California, Hawaii, Oregon and Washington. The states to the east of California are in the Rocky Mountain region, which includes Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Wyoming and Utah. States that lie south of California are considered to be part of the Southwest region.