The 1836 U.S. Patent Office fire was the first of two major fires the U.S. Patent Office has had in its history. It occurred in Blodget's Hotel building, Washington on December 15, 1836. An initial investigation considered the possibility of arson due to suspected corruption in the Post Office, which shared the same building, but it was later ruled out. The cause was ultimately determined to be accidental. The fire is considered to be a unique point in the historical events of the Patent Office that caused policy changes.
Local fire suppression efforts were incapable of preventing the damage due to lack of fire personnel and proper equipment. Many patent documents and models from the preceding three decades were irretrievably lost.