The Chesapeake–Leopard affair was a naval engagement off the coast of Norfolk, Virginia, on June 22, 1807, between the British fourth-rate HMS Leopard and the American frigate USS Chesapeake.

President Thomas Jefferson initially attempted to use this widespread bellicosity to diplomatically threaten the British government into settling the matter.

The United States Congress backed away from armed conflict when British envoys showed no contrition for the Chesapeake affair, delivering proclamations reaffirming impressment.

[1] On June 22, 1807, during the Napoleonic Wars, several British naval vessels were on duty on the North American Station, blockading two French third-rate warships in Chesapeake Bay.

Decatur received a letter from the British consul ordering him to turn over three men alleged to have deserted from HMS Melampus.

[5] Chesapeake was off the coast of Norfolk, Virginia, commanded by Commodore James Barron, when Leopard, under Captain Salusbury Pryce Humphreys, encountered and hailed her.

[6] Daniel Martin, for instance, claimed he was born in Westport, Massachusetts; he was described as age 24, 5 feet 5+1⁄2 inches (166 cm) high with "woolly hair", black eyes and dark yellow complexion and a small scar over his right eyebrow.

[14] After over 5 years spent in bonded service with the Royal Navy, the last two deserters were returned to Boston, Massachusetts by the schooner HMS Bream, one month after the outbreak of the War of 1812.

[16] Americans of every political stripe spoke of the need to uphold national honor, and to reject the dismissal of the United States by Britain as a third-class nonentity.

"[18][19] James Monroe, then a foreign minister acting under instructions from U.S. Secretary of State James Madison, demanded British disavowal of the deed, the restoration of the four seamen, the recall of Admiral Berkeley, the exclusion of British warships from U.S. territorial waters, and the abolition of impressments from vessels under the United States flag.

Many Americans demanded war because of the attack, but President Jefferson turned to diplomacy and economic pressure in the form of the ill-fated Embargo Act of 1807.

The public was shocked that Chesapeake had not been able to put up any resistance and surrendered so quickly, questioning the ability of the Navy to defend the country in the case of a war with Great Britain, despite the expensive and controversial frigate-building program.

Though the United States and Great Britain are at peace at the time, and neither he nor any member of his crew had any direct involvement with the affair, he is met with mistrust and hostility from American whalers due to their negative association with the ship.