Second Barbary War

BelligerentsUnited StatesRegency of AlgiersCommanders and leadersJames Madison
Stephen DecaturOmar Agha
Raïs Hamidou†Strength 3 frigates
3 brigs
2 schooners
2 sloops 5 frigates
7 smaller warshipsCasualties and losses 10 killed
30 wounded 53 killed
Many wounded
486 captured
2 ships captured
1 ship sunk

The Second Barbary War, also known as the U.S.–Algerian War and the Algerine War, was a brief military conflict between the United States and the North African state of Algiers in 1815.

Piracy had been rampant along the North African "Barbary" coast of the since the 16th century. Algerian pirates and privateers intermittently preyed on American ships, with Algiers extracting annual tribute from the U.S. since 1795; the First Barbary War in the early 19th century, fought primarily against Algiers' neighbors, failed to stop the problem.

In February 1815, after the end of the War of 1812, U.S. president James Madison requested that Congress declare war against Algiers; legislation was passed on 3 March 1815 authorizing the use of the U.S. Navy to protect American interests and seize Algerian assets. In May, a 10-ship squadron led by Commodore Stephen Decatur—a veteran of the First Barbary War—sailed from New York to Algiers. An even larger force, led by Commodore William Bainbridge, another Barbary War veteran, was close behind.

Following a decisive U.S. victory off the coast of Cape Gata in June 1815, Commodore Decatur successfully pressed DeyOmar Agha of Algeria to sue for peace. The resulting agreement was formalized in a treaty ratified by the U.S. Senate on 5 December 1815. However, Agha later repudiated the treaty, as well as similar agreements with several European nations, until a combined Anglo-Dutch force bombarded Algiers in 1816; the subsequent arrival of a U.S. squadron carrying U.S. commissioner William Shaler led to a new but substantially similar treaty on 23 December 1816, which was ratified on 11 February 1822.

The Algerian War resulted in the United States and Europe ceasing tribute to Algiers and marked the beginning of the end of piracy in the Mediterranean. It also elevated U.S. military prestige and power since the prior Barbary War. Western nations built ever more sophisticated and expensive ships that the Barbary pirates could not match in numbers or technology, and the French conquest of Algeria in 1830 fully ended any vestige of piracy in the region.