Jack's Boathouse. (Photo by Isaac Brooks)

Jack’s Boathouse, the Georgetown landmark that has rented kayaks and canoes to generations of Washington residents and visitors, is being evicted by the National Park Service.

In a letter dated Dec. 18, the Park Service advises owner Paul Simkin that his lease will be terminated.

Four years ago, Simkin liquidated his retirement savings to upgrade Jack’s. He said his business has been booming since.

“I’m brokenhearted,” said Simkin, who said he has always paid his rent. “It will cost me a fortune to break this place down.”

The Park Service said Sunday that the lease was no longer considered valid but did not explain. The agency said, however, that the recreational activities offered there are important and will be provided as a concession. It also said that Simkin was free to offer a proposal to operate the concession.

Simkin has been calling his 27 employees to let them know that Jack’s must vacate by the end of January, and they will be out of a job.

Jack’s, which sits on the Georgetown waterfront near Key Bridge, was opened in 1945 by Jack Baxter, a D.C. police officer.who was a D.C. police officer for more than a decade on the Georgetown beat.

When he died in 1999, son Frank Baxter took over the boathouse. He called it “a little country place in the middle of the city.”

Simkin was Frank Baxter’s best friend and helped him run the business until Baxter died about four years ago.

After Baxter died, Simkin put about $300,000 into improvements, and the business went from 4,000 customers during a summer season to 72,000 last summer, Simkin said.

“It’s one thing if we were going out because we’re not doing our job,” Simkin said. “I’d feel better [about the notice] if we were failing.”

Simkin said the last contact he had with the Park Service was several months ago when officials were talking about giving him a three-year lease.

Friends and customers have started a “Save Jack’s Boathouse from Closure” Facebook page and a petition asking officials, including President Obama, to keep the boathouse open.

The Park Service said it expected no interruption in activities at the site.

At least one presidential family has used Jack’s.

During the Kennedy administration, Jacqueline Kennedy, along with John Jr. and Caroline, took a Potomac River ride in one of the rowboats. Secret Service agents followed in another boat.

Notables continued to be drawn to the place. Actor Tony Danza was a regular. And D.C. Council member Jack Evans (D-Ward 2) had his wedding reception there a few years ago.

Simkin said he’ll sell the 300 boats. He doesn’t know what else to do.

“I’m devastated by this,” he said.