Geography of the United States York City, and includes the Florida peninsula. Areas further inland feature rolling hills, mountains, and a diverse collection of temperate and subtropical moist and wet forests. The Appalachian Mountains form a line of low mountains separating the eastern seaboard from the Great Lakes and the Mississippi Basin. The five Great Lakes are located in the north-central portion of the country, four of them forming part of the border with Canada, only Lake Michigan situated entirely within United States. The southeast United States, generally stretching from the Ohio River on south, includes a variety of warm temperate and subtropical moist and
Mainland invasion of the United States the U.S. economy, such as efforts to devalue the dollar or corner trade markets to isolate the United States, are currently considered another method by which a foreign power may seek to attack the United States. Many experts have considered the United States to be entirely uninvadable, because of the country's major industries, reliable and fast supply lines, large geographical size, population size, difficult regional features, and strong military force. For example, the deserts in the Southwestern United States and the Great Lakes in the Midwestern United States insulate the major U.S. population centers from threats of invasion. An invasion