The Hotel Harrington, which turns 100 this month, is the oldest continuously operating hotel in the District. In the 1950s, a television studio in the hotel was the setting for “The Milt Grant Show,” Washington’s answer to “American Bandstand.” (Washington Star)

Sometime in the next few years, Donald Trump will open a mega-luxury, mega-expensive hotel on Pennsylvania Avenue NW. It will not affect the bottom line of the Hotel Harrington, a block away at 11th and E streets.

The sign on the corner of the Harrington announces it as “Washington’s Tourist Hotel.” And so it is. At a time when the word “tourist” can have a down-market tinge to it, the Hotel Harrington unabashedly appeals to the family on a budget, the Midwestern school group, the sightseeing European.

“A Vienna choir just left yesterday,” Ann Terry, Harrington general manager, said when I visited her in her office last week. “We had the West Point cadets a couple of weeks ago. They come every year.”

February and March are big for school groups from the United Kingdom. In September and October, they come from Germany.

“A lot of Europeans come,” Ann said. “They’re familiar with this style of hotel. They’re perfectly happy with the fact that it’s older and not super modern.”

Older it definitely is. The Harrington opened on March 1, 1914, making it the District’s oldest continuously operating hotel. (Don’t let the Willard or the Hotel Washington pretend to be the record-holders. Both have closed in the past for extensive renovations.)

Harrington Mills and Charles McCutcheon were the business partners who opened the hotel’s six-story building a century ago. Two 12-story additions have since been added. There are a total of about 300 rooms, plus two restaurants: Harry’s Bar and Harriet’s. The hamburger joint Ollie’s Trolley leases space on a corner.

There was a time when the Harrington had a certain profile in Washington. In 1938 it became the city’s first air-conditioned hotel. It had a bar called the Pink Elephant Cocktail Lounge and a cafeteria called the Kitcheteria. It was home to D.C.’s first TV station: DuMont’s W3XWT, now known as WTTG-Channel 5. In the 1950s, “The Milt Grant Show,” Washington’s version of “American Bandstand,” was transmitted live from the Harrington.

Today, though, it’s fair to say that most Washingtonians are unaware of the hotel. Why would we be? We don’t stay in hotels. We live here. And when we see the Harrington, we might think: What is that doing here, in the middle of so much expensive real estate?

“I inherited this place, and it’s my job to keep it running,” said Charles McCutcheon, grandson of the co-founder. On Saturday, various McCutcheons were at the Harrington for a birthday party. So were the Wooters, descendants of the Mills family. Brendan Wooters, 3 ½, representing the sixth generation, eyed a cake in the shape of the hotel.

Charles, 84, is a nuclear physicist who lives in Bethesda. I’d heard he was into aviation. He once designed a paper airplane that advertised the hotel and was given to guests. And it was Charles who arranged to get some of the posters that hang in the Harrington’s hallways: photos of passenger jets and their cockpits.

“They were free,” he explained. “Boeing and Airbus would send them to us.”

Thrift is a Harrington specialty. Rooms start at around $125 and top out at around $199. The rates and location bring a lot of repeat customers.

“The thing I think is important is it’s not a chain,” said Lisa Warnecke, a government consultant from Syracuse, N.Y., who first stayed at the Harrington 20 years ago. “Here you meet real people. It’s hard to meet real people in downtown these days.”

A lot of real people work at the hotel, too, and have a for a long time. Terry studied zoology in her native England, worked on animal vaccines for Pfizer, then wound up at the Harrington through a friend. That was in 1986. She’s 78 and shows no sign of slowing down.

Nadim Anthony went full time the same year. He started out washing dishes. Now he’s the front desk agent. John Matthews started 34 years ago. He paints, fixes locks and does other maintenance. His older brother, Wendell, works at the Harrington, too.

John Boyle, who runs the Harrington’s two restaurants, has been there 22 years. “And they still call me the new guy,” he said.

At Saturday’s party, various bits of Harrington memorabilia were on display, including an old silver water jug obviously filched by a thieving guest and bought back via eBay.

John McClow, the hotel’s controller, had framed the hotel’s 1915 tax bill: $808.43.

“Believe me,” he said, “it’s not that low anymore.”

I wonder: Will any of Trump’s hotels be here a century from now?