The United States is a country in the Western Hemisphere. It consists of forty-eight contiguous states on the North American continent; Alaska, an enormous peninsula which forms the northwestern most part of North America, and Hawaii, an archipelago in the Pacific Ocean.

It also holds several United States territories in the Pacific & Caribbean. The country shares land borders with Canada and Mexico and a water border with Russia.

The United States shares land borders with Canada (to the north) and Mexico (to the south), and a territorial water border with Russia in the northwest. The contiguous forty-eight states are otherwise bounded by the Pacific Ocean on the west, the Atlantic Ocean on the east, and the Gulf of Mexico to the southeast.

Alaska borders the Pacific Ocean to the south, the Bering Strait to the west, and the Arctic Ocean to the north, while Hawaii lies far to the southwest of the mainland in the Pacific Ocean.

Forty-eight of the States are in the single region between Canada and Mexico; this group is referred to, with varying precision and formality, as the continental or contiguous United States, and as the Lower 48. Alaska, which is not included in the term contiguous United States, is at the northwestern end of North America, separated from the Lower 48 by Canada.

The State of Hawaii is an archipelago in the Pacific Ocean. The capital city, Washington, District of Columbia, is a federal district located on land donated by the state of Maryland. (Virginia had also donated land, but it was returned in 1847.) The United States also has overseas territories with varying levels of independence and organization.

Due to its large size and wide range of geographic features, the United States contains examples of nearly every global climate. The climate is temperate in most areas, tropical in Hawaii and southern Florida, polar in Alaska, semiarid in the Great Plains west of the 100th meridian, Mediterranean in coastal California and arid in the Great Basin.

Its comparatively generous climate contributed (in part) to the country's rise as a world power, with infrequent severe drought in the major agricultural regions, a general lack of widespread flooding, and a mainly temperate climate that receives adequate precipitation.