The last man to attack the US Capitol, prior to the events on 6 January 2021, was a British Army Major General from Northern Ireland, in 1814.
The Belfast Telegraph published an article that claimed the last time the US Capitol was attacked was during the War of 1812: "Robert Ross … from Rostrevor in Co Down, will always be remembered as the man who burned down the White House in 1814." The US Capitol comprises the buildings that house both the US House of Representatives and the US Senate. But was Robert Ross really the "last man to attack the US Capitol?" We reviewed incidents of the US Capitol buildings being attacked. [...] There have been four notable attacks on the US Capitol in-between Robert Ross and the incident on 6 January 2021. While Major General Robert Ross in 1814 was the last foreign attacker, Linda Evans and Laura Whitehorn were among the most recent attackers in 1983.