Prior to the burning, 4,500 British soldiers went up against 5,000 Americans (mostly militiamen) in a battle at Bladensburg, Maryland, just 4 miles northeast of Washington. Though the Americans had the advantage of numbers and artillery, the untried and poorly led militiamen didn’t stand much of a chance against the better trained and disciplined British soldiers. Three hours of battle had the Americans fleeing as fast as they could, while the British commanding officers, General Ross and Admiral Cockburn, led a portion of their men into Washington, which was now undefended.
Leaving private homes and property alone for the most part, the British began burning government buildings, starting with Capitol building, which at the time also housed the Supreme Court and Library of Congress. They then proceeded to the White House, which had been abandoned by President Madison and his wife shortly before. (Dolley Madison is famous for staying at the White House as long as possible and directing the rescue of a portrait of George Washington, among other valuables.)
The following day, Cockburn and Ross organized the burning of other buildings, like the State and War departments and the Treasury, which had started to burn the night before but had been doused by a rainstorm. Cockburn ordered the destruction of the printing presses of a newspaper that had been particularly critical of him, but the U.S. Patent Office was saved from destruction by the pleas of its superintendent. The British went to the Navy Yard, but it had already been burned the previous day by the Americans to keep it from falling into British hands. A contingent of soldiers also went to Greenleaf Point Federal Arsenal to destroy the gunpowder and cannons there but ended up causing an explosion that killed or maimed many of them.
Later that day, a huge storm blew in that wreaked havoc on the city, downing trees and ripping roofs off buildings. After the storm had died down somewhat, the British officers ordered a retreat of their men during the night, before the American forces could regroup.
Discover more about the burning of Washington DC, and other events and people of the war, in Fold3′s War of 1812 collection.