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The Lure of Imperialism

This map is part of a series of 20 animated maps showing the history of The United States: a territorial history.

The end of the Civil War and the re-establishment of a united nation revived the impetus for conquest and the United States began to look beyond its frontiers.

William Henry Seward, Secretary of State under Abraham Lincoln and Andrew Johnson, was particularly keen to develop the United States’ presence. He began by negotiating with Russia for the purchase of Alaska in March 1867.

In the same year, the United States moved out of their continental base by occupying and then buying the Midway Islands (August 1867).

Further expansion focused principally on two regions, the Caribbean-Central American region and the Pacific Ocean:

In 1878, the US occupied the Pago Pago base on the island of Samoa

In 1887, it obtained the concession for Pearl Harbour

But, the Hispanic-American War in 1898 was to mark the high point of American expansionism. During negotiations for the Treaty of Paris in December 1898, Spain handed over to the United States:

Porto Rico in the West Indies

The island of Guam in the Marianas Archipelago

And the Philippines, for which it paid $20 million.

The annexation of Hawaii, in the same year, completed American acquisitions in the Pacific.

This desire for influence beyond its continental frontiers was further confirmed in the early 20th century.

In 1901, the Platt amendment effectively placed the island of Cuba under the protection of the United States.

The United States also obtained control of the isthmus of Panama where the Panama Canal was built between 1906 and 1914.