RTFORD — Sen. Chris Murphy, D-Conn., has relocated his office to the former Colt manufacturing complex in the building under the blue, onion-shaped dome.

Murphy said Monday he is taking a stake in the Colt Gateway redevelopment by leasing space in the East Armory, visible from I-91 and one of the oldest structures on the property.

"The community at Colt Gateway is connecting businesses and Hartford residents to the historic birthplace of Connecticut manufacturing," Murphy said.

Murphy's East Armory office opened Friday and encompasses about 3,500 square feet. The new office replaces one on the seventh floor of One Constitution Plaza.

The East Armory is one of 10 structures that are part of the Colt Gateway redevelopment that includes office space and apartments. Of the 112,000 square feet in the East Armory, 60 percent, or 66,000 square feet are leased. In addition to Murphy, other tenants are JCJ Architecture, Insurity and the Greater Hartford Academy of the Arts.

Larry Dooley, owner of CG Management and a partner in the redevelopment, said Insurity may exercise an option to lease 15,000 square feet on the third floor of the East Armory. CG Management said an IT company has shown interest in about 12,000 square feet on the first floor. Dooley declined to name the company because discussions were in the early stages.

Colt Gateway is part of the Coltsville National Historical Park, which could officially open next spring. The National Park Service is working to draw attention to the park before the official opening, assigning a park ranger to give tours on weekends.