US Geography Spans Borders, States, Lakes, Mountains

Interstate 5 is the only U.S. Interstate whose numbered route reaches both the Mexican and Canadian borders, running from San Diego’s San Ysidro crossing to the Peace Arch in Blaine, Washington. Lake Superior, spanning four U.S. states and Ontario, was rated the country’s cleanest lake in a Lake.com study, which gave it a zero pollution score. The Appalachian Mountains extend across 18 states and into Canada, with West Virginia the only state located entirely within the Appalachian region; the Appalachian Trail runs from Georgia to Maine. The Mississippi River borders 10 states, forming several separate interstate boundaries, though its total length is not the same as the length of any single state border.