Mid-April is a lousy time to have a holiday in Maine. What do we really have to celebrate? Mailing in our tax returns? Confronting the trash left behind by the retreating snowdrifts?

Many of us would gladly trade a sunny day off in August or June for the windswept early spring holiday left to us by our forebears and celebrated by only us and our fellow New Englanders in Massachusetts.

Which is not to say that the date is unworthy of remembrance. On April 19, 1775, about 700 British army regulars marched toward Concord, Mass., to seize a stash of arms they believed was hidden there and to arrest revolutionary leaders Sam Adams and John Hancock.

But their secret mission was uncovered by a colonial spy network, and the word was sent to rouse an army of farmers to stop it. The first shots were fired at the Lexington green and the flustered British continued on to Concord where they were defeated in battle by about 500 militiamen. Their mission a failure, the British beat a hasty retreat to Boston, and along the road were harassed by revolutionary guerrillas.

The battles marked the start of the Revolution and were immortalized by Ralph Waldo Emerson as “the shot heard ’round the world.” The story of the intelligence operation that led up to the big day was put into verse by Portland’s own Henry Wadsworth Longfellow, who gave an enhanced role to a Boston silversmith named Paul Revere.

The poem has a few historical inaccuracies. The lantern signal from the Old North Church was sent by Revere, not to him. And he was one of several riders, not, as the poem suggests, a solo practitioner.

But the story echoes over time because even though the poet took liberties with the facts, the greater truth endures: A band of dedicated people fighting for their independence can be more powerful than the army of an empire.

And while Emerson may not have been literally correct, the message that a free people could govern itself effectively for more than two centuries has been heard not only around the world, but through time, from deep behind the Iron Curtain to the streets of Cairo.

July 4 may be a better time to take a long weekend, and we will have 48 more states joining us in the party.

But Patriots Day remains important too, and a day well-worth celebrating — even if it does come at a lousy time of year.