April 19, 1775 — A battle began today that didn’t end until March 17, 1776 when the British finally fled Boston by sea. The 11-month battle started when British troops retreated to Massachusetts after the Battles of Lexington and Concord.

Here’s what happened: American militiamen blocked off Boston neck and Charlestown neck, the thin strips of land connecting the Boston and Charlestown peninsulas to the mainland, to prevent the British from conducting anymore attacks on the surrounding countryside. Any movement in or out of the city, whether it be military or civilian, was completely cut off. On April 22, British General Thomas Gage met with town officials to work out a deal that would allow civilians to leave or enter Boston.

Sources

• historyofmassachusetts.org
• "After the Siege: A Social History of Boston 1775-1800"