Electric Boat will relocate some 400 designers and engineers working at its Fort Trumbull facility in New London to Eagle Park, the vacant Mashantucket Pequot-owned property that straddles the North Stonington-Stonington line near Exit 92 of Interstate 95.

The shipbuilder plans to start moving employees, including a small team supporting warehouse operations, in mid-September, according to Liz Power, an EB spokeswoman.

EB and the tribe reached agreement on a five-year lease, Power said. Terms were not disclosed.

Collier’s International, the global real estate company that represented the tribe in negotiations, announced late last week that EB will occupy all of the 125,000 square feet of space available at the site.

“It’s a very good thing for the tribe, for EB and for the local economy to repurpose that building,” said John Cafasso, a Collier’s principal.

David Rozen, the tribe's chief financial officer, said the agreement "makes sense from a business perspective."

EB had entered the local real estate market in search of office space, and, after touring Eagle Park, decided to also lease the available warehouse space there, Cafasso said. The main, three-story building on the property contains some 53,000 square feet of office space on the second and third floors and more than 72,000 square feet of high-bay warehouse space, according to Collier’s.

CBRE/New England represented EB in the transaction.

Built in 1989 to house MAN Roland’s printing press-manufacturing operation, the main structure was erected on about 40 acres in Stonington. The property includes another 35 acres in North Stonington and has a North Stonington address of 25 Norwich-Westerly Road (Route 2).

The Mashantuckets, whose Foxwoods Resort Casino is located about eight miles north on Route 2, purchased the property in 1995, with MAN Roland, then in need of more space, moving to tribe-owned property in Groton. The German firm later moved its U.S. operations out of the state.

The tribe paid a total of $16.5 million for the property, town records show. The tribe added a second building, dubbed the Foxwoods Technical Center, in 2002.

The main building served as the tribe’s employment office and as a training site for Foxwoods’ gaming employees. It closed last year, with the employment office moving to Foxwoods, and other offices relocating to the Mashantucket Pequot Museum and Research Center, according to a spokeswoman for the tribe.

Some Foxwoods retail outlets had stored merchandise on the property.

Electric Boat purchased its Fort Trumbull facility from Pfizer in 2010, and has maximized its use of the space there, Power said. At its peak, Pfizer had about 1,800 people working in the building. More than 3,500 EB employees, mainly engineers and designers, work there now.

EB, on a hiring spree in recent years due to increased submarine production, has about 17,000 employees in total, 11,800 of whom work in Connecticut.

Day Staff Writer Julia Bergman contributed to this report.

b.hallenbeck@theday.com