The great fire of Portland, Maine, sometimes known as the 1866 great fire of Portland, occurred on July 4, 1866—the first Independence Day after the end of the American Civil War. Five years before the Great Chicago Fire, this was the greatest fire yet seen in an American city.
A major conflagration struck Portland, Maine, on July 4, 1866—the first anniversary of U.S. independence following the end of the Civil War. This disaster occurred five years before the infamous Great Chicago Fire, which was then the largest urban blaze in American history.