March 17 is Evacuation Day, a holiday observed in Suffolk County (which includes the city of Boston) and also by the public schools in Cambridge and Somerville, Massachusetts. The holiday commemorates the evacuation of British forces from the city of Boston following the Siege of Boston, early in the American Revolutionary War. Schools and government offices (including some Massachusetts state government offices located in Suffolk County) are closed. If March 17 falls on a weekend, schools and government offices are closed on the following Monday in observance. It is the same day as Saint Patrick's Day, a coincidence that played a role in the establishment of the holiday.