Brooklyn Trader Joe's Built on Top of George Washington's Old Fort

The 239th anniversary of the Battle of Brooklyn is upon us, and history nerds across the borough are polishing their brass buttons for a packed weekend of Revolutionary War reenactments.

We also have said nerds to thank for a treasure trove of geographical info about the battle posted online — where it began, which roads and bridges the American and British armies each took, where they sneaked up on each other and blew each other to bits, etc.

Our favorite historical site from the battle, though, has got to be the old fort that formerly stood on the same ground as present-day Trader Joe’s in Cobble Hill, then called Ponkiesberg. Yes, Ponkiesberg.

(Big hat tip to DNAinfo, who pointed it out first.)

According to city historians, the site, a former hill, ”served as an observation post from which General [George] Washington saw the Battle of Brooklyn. Upon seeing the actions of Smallwood’s Marylanders he was heard to say, ’What brave men I must this day lose.’”

Today, a tarnished plaque greets Trader Joe’s shoppers on their way into the building.

“Near this place during the Revolutionary War,” it reads, “stood the Ponkiesberg fortification from which General George Washington is said to have observed the fighting at Gowanus.”

Less publicized is the fact that Washington later lost the battle, and was forced to retreat to Manhattan.

When he did, city historians write, the British ”leveled the hill so that it could not be used by the Americans at a later time.”

Little did they know that one day — some 239 years later — their new flattop would be used by the Americans in pursuit of the most American of American dreams: shopping at Trader Joe’s.

So if Revolutionary War reenactments aren’t your thing, at least take some time out of your regular TJ’s run this weekend to pay respects to the plaque of General Washington. Also heed the giant flagpole sticking from the top of the grocery store, which marks the height of the hill on which Washington stood as he drove his troops to the death — all for your freedom to stock up on cheap organics and craft beers.

Below, a full lineup of Battle of Brooklyn festivities this weekend, courtesy of the New York Times.

Saturday

• The Old Stone House in Brooklyn hosts a Remembrance Ceremony. 12 p.m. (Free)

• A dramatic reading of the Declaration of Independence at the Vander Ende-Onderdonk House in Ridgewood. 1 p.m. (Free)

• Take a Battle of Brooklyn-themed walking tour of the borough with William J. Parry, an archaeology professor. 4 p.m. ($12; registration required)

Sunday

• It’s the main event: Re-enactors and costumed historical figures gather to commemorate the battle in Green-Wood Cemetery, with games, cooking demonstrations and a parade. 12:30 p.m. (Free)

• Or, at any time, you can take your own tour of the Revolutionary War-era sites in the borough with a podcast, or play an online game about the battle.