From Wikipedia:

"On August 24, 1814, after defeating the Americans at the Battle of Bladensburg, a British force led by Major General Robert Ross occupied Washington City and set fire to many public buildings, including the White House and the Capitol, as well as other facilities of the U.S. government.[3] The attack was in part a retaliation to American actions in the Raid on Port Dover.

Throughout the history of the United States, the U.K. is the only country to have ever burned the White House or Washington, D.C., and this was the only time since the American Revolutionary War that a foreign power captured and occupied the United States capital."