When a bar begins the timeline on its website with “Puritans arrive at Plymouth Rock,” there’s a good bet the spot has some history behind it.

And when it comes to that history, the Union Oyster House—a National Historic Landmark—doesn’t mess around.

The first of the three buildings that now make up the bar/restaurant was built as a private residence in the early 1700s—no one’s sure exactly when. By the time the Americans were plotting their split from the Brits it was playing host to Isaiah Thomas (1771-1775), who published the incendiary (at least in British eyes) tabloid Massachusetts Spy; the paymaster of the Continental Army (1775); and a fella by the name of Duc de Chartres (later, King Louis Philippe) who taught language lessons to locals while in exile during the French Revolution (1796).

The Union Oyster House itself opened as Atwood’s Oyster House in 1826, making it the oldest continually operating business of its kind in the country. Since then, two separate buildings have been added and the oyster house has expanded.

Around 1890, the toothpick was introduced to America in this very spot, and by 1916—the same year the current name took affect—the coal-fired range where oysters are still roasted was installed in the building’s kitchen.

The list of celebrity sightings here is long and distinguished, and includes Robin Williams, Larry Bird, and of course, Alanis Morrisette. Presidential patrons to the Union Oyster House include Calvin Coolidge, Franklin D. Roosevelt, Bill Clinton, Barack Obama, and JFK, who is said to have visited the establishment at noon nearly every Sunday he was in Boston for lobster stew. Booth 18, in the upstairs dining room, was apparently his favorite.

As of 2003, the record for most oysters eaten at the bar in a single sitting was 120. The feat was accomplished by Frank Kelleher at an unknown date. Also unknown: whether Frank survived the ordeal.

These days, the tradition of serving Boston baked beans gratis every Sunday and offering patrons a glass of iced tea whenever the temperature exceeds 85 degrees continues.

Location: 41 Union St., Boston, MA 02108

Hours: Sunday-Thursday, 11 a.m.-9:30 p.m.; Friday-Saturday, 11 a.m.-10 p.m. (bar open until midnight).

You’re Having: Oysters and a cold one.

Little Known Fact: Former president of Haverford College, Jack Coleman “worked as a salad man here in total anonymity” (though no one’s quite sure who might have actually recognized him) for months during his sabbatical in an effort to learn more about “one of America’s most rigorous jobs and lifestyles.”

Best Yelp Review: “This is a must when visiting Boston. Its history alone is a good enough reason to dine here.”—Trina-Jo P.