Photo: Most retail shops and offices are open on Patriots’ Day

Patriots’ Day, the Bay State’s homegrown holiday, commemorates the battles of Lexington, Concord, and Menotomy on April 19, 1775, the first of the American Revolutionary War. 

While the first shot was fired in Lexington and the Regulars were halted at North Bridge in Concord, more than half of all casualties that day occurred in modern-day Arlington. Minutemen from surrounding towns converged on Menotomy to ambush the British over the short distance from Foot of the Rocks (at the intersection of Lowell Street and Massachusetts Avenue) to Spy Pond on their retreat back to Boston.

Arlington will celebrate on Patriots’ Day to greet National Lancers riders reenacting Paul Revere and Williams Dawes’s famous ride warning, “The Regulars are out!” The celebration will occuz r at Whittemore Park, in front of the Cyrus Dallin Art Museum, 611 Mass. Ave. While awaiting the riders, you’re invited to join the activities: crafts, snacks, and a scavenger hunt beginning at 11 a.m. The riders are expected around noon.

Most of the day’s attention is focused on the Boston Athletic Association’s annual 26.2 miles marathon. It will be a great day for runners and fans as the forecast calls for highs in the mid-60s, with some clouds during the race.

So, what’s opened and what’s closed?

Closed

• Belmont Town Hall, offices, and buildings are closed, as is the Belmont Public Library currently in the Beech Street Center and the Benton Library.
• Belmont public schools are closed Monday as they are shut for the week-long spring-time break.
• State offices such as the Register of Motor Vehicles and courts are closed.

Due to the holiday, trash and recycling curbside pickup is delayed a day. If your removal day is Monday, don’t! Bring it to the side of the road on Tuesday.

And Massachusetts residents get an extra day to submit or mail their federal and state taxes. The deadline is Tuesday, April 16 at 11:59 p.m.,

Open

As it is a state holiday, the US Post Offices on Concord Avenue and in Waverley Square are open as are federal offices.

Star Market on Trapelo Road is open as are retail and convenience stores, eateries and restaurants, and liquor establishments.

Marathon Monday on the MBTA

While the Red Line subway at Harvard and Alewife will be running on a weekday schedule, buses are on a weekend timetable. In addition:

• Various bus routes on the marathon route’s North and South sides will be detoured.
• Due to congestion, bikes are prohibited on any MBTA vehicles on Patriots’ Day.
• Copley Station will be closed Monday. 
• View the MBTA’s Patriots’ Day schedule here