In 1894 the Lexington Historical Society petitioned the Massachusetts State Legislature to proclaim April 19 as "Lexington Day". Concord countered with "Concord Day". Governor Frederic T. Greenhalge opted for a compromise: Patriots' Day. However the biggest battle fought on this day was in the town of Menotomy, now Arlington, Massachusetts. Menotomy was on the Concord Road between Lexington and Concord and Boston. While the fighting was going on in Lexington and Concord, 5,100 militia men arrived in Menotomy from Middlesex and Essex Counties. These men took up positions along the road the British troops would take on their retreat to Boston. They placed themselves in and around houses, stone walls, fields and barns. The bloodiest fighting of the first day of the American Revolution took place inside a single house, the Jason Russell House, in Menotomy. Eleven militia men died in this house fighting British troops trained in bayonet fighting.
Patriots' Day was first proclaimed in Massachusetts in 1894 by Gov. Greenhalge replacing Fast Day as a public holiday. The idea was introduced to the Governor by the statesman from Lowell, Isaac Henry Paige. It was established on April 19, commemorating the date of the Battles of Lexington and Concord and the larger Battle of Menotomy in 1775, and consolidating the longstanding municipal observances of Lexington Day and Concord Day. It also marked the first bloodshed of the American Civil War in the Baltimore riot of 1861, during which four members of the Massachusetts militia were slain and 36 injured. In Menotomy, now Arlington, 25 militia men died and 40 British soldiers were killed. The dual commemoration, Greenhalge explained, celebrated "the anniversary of the birth of liberty and union". It is likely that the battles that took place in Menotomy are not as well known as the smaller battles in Lexington and Concord because the town has had several names since that day in 1775. In 1938, with the generation that had fought in the Civil War largely off the voter rolls, the Massachusetts legislature passed a bill establishing the holiday "in commemoration of the opening events of the War of the Revolution".
Maine followed Massachusetts in 1907 and replaced its Fast Day with Patriot's Day.
On June 10, 2017, Governor Dannel Malloy signed a bill establishing Patriots' Day as a statewide unpaid holiday in Connecticut. On April 16, 2018 Connecticut became the 4th state to recognize the holiday.