History of U.S. Land Acquisitions Between 1803 and 1917, the United States acquired more than 1,388,000,000 (2,168,750 square miles, or 5,617,000 square km) acres of land. (more) History of U.S. Land Acquisitions Written by Mindy Johnston Mindy Spitzer Johnston is Managing Editor at Encyclopædia Britannica. Mindy JohnstonAll Fact-checked by Britannica Editors Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Britannica Editors Last updated Jan. 30, 2026 •History Over the course of a little more than a century, the United States transformed from a young republic along the Atlantic seaboard into a continental—and overseas—power through westward expansion and territorial additions. The map and table below reveal the monumental impact of seven major land acquisitions between 1803 and 1917. Today—even after a loss of more than 85 million acres (132,810 square miles, or 343,980 square km) when the Philippines gained independence in 1946—the United...

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