The "Mainland United States" refers to the contiguous 48 states located on the North American continent, excluding Alaska and Hawaii. This region stretches from the Atlantic Ocean in the east to the Pacific Ocean in the west, and from Canada in the north to Mexico in the south. It encompasses a diverse range of landscapes, climates, and cultures, making it a unique area within the country. The mainland is home to major cities such as New York City, Los Angeles, and Chicago, which are known for their economic, cultural, and historical significance. Additionally, it includes various national parks, such as Yellowstone and Yosemite, showcasing the natural beauty and biodiversity of the region.