Already one of the biggest projects in the state, the 56-acre Assembly Row development includes several large apartment buildings, a recently completed MBTA station, and dozens of outlet stores and restaurants. On Monday, officials formally began construction of a 750,000-square-foot office headquarters for Partners HealthCare.

Mayor Joseph Curtatone said Monday that the city will consider making road and utility upgrades to encourage additional construction on 73 acres that abut the Assembly Row complex.

Somerville officials are exploring plans to double the size of the massive Assembly Row project by allowing construction of homes, stores, and offices on surrounding property along Interstate 93.


“There is a great amount of velocity and energy in Somerville that the development community wants to be a part of,” Curtatone said. “Over the next year, we as a community will script out what we want to be built on the remaining parcels.”

The additional 73 acres are situated between Interstate 93 and the existing Assembly Row development site along Grand Union Boulevard. The property is occupied by the Assembly Square Marketplace, a Home Depot, and a large office building and other businesses.

Somerville officials want the property to more closely resemble the dense city blocks at Assembly Row, where stores and restaurants are situated below new office space, apartments, and parking garages. They acknowledged that vision would probably take another 10 years or more to implement, as many of the properties within the 73 acres are owned by private entities that may not want to redevelop them in the near future.

Curtatone said he expects construction around Assembly Square to continue for 20 years. He has already laid out goals to build as many as 9,000 homes in the area to accommodate surging demand for housing from young professionals and others moving into urban neighborhoods.

“We’re in the midst of the greatest demographic shift in this nation’s history,” Curtatone said. “Somerville is in the middle of that, and developers want to profit from it. We want to leverage that profit motive to meet our community goals.”


The mayor has asked the Board of Aldermen to appropriate $500,000 to hire consultants to help plan uses for the 73 acres during the next year. The effort will identify road improvements and other upgrades needed to accommodate additional development.

The neighborhood’s economic future got a huge boost Monday when construction formally began on the Partners HealthCare headquarters. The project will bring to Assembly Row more than 4,500 administrative employees who are now scattered among 14 sites around the region.

The city wants to improve infrastructure between I-93 and Assembly Row to encourage more city-block-style development. DAVID L. RYAN/GLOBE STAFF

Those employees will be housed in a 13-story building with 100,000 square feet of ground-floor retail space that’s expected to contain a health club, stores, and restaurants.

“This is a huge validator of the vision we’ve laid out here,” said Don Briggs, an executive with Assembly Row developer Federal Realty Investment Trust. “The quality of that company makes this a location that everybody has to look at.”

In addition to the 13-story building and an adjacent parking garage, Partners has an option to build another 300,000 square feet of offices at Assembly Row. Future development will also bring another 1,400 homes, additional outlet stores, a hotel, and office buildings.

Briggs said Federal Realty, which also owns Assembly Square Marketplace, has explored buying additional property within the adjacent 73 acres. But so far, he said, the company has not found a seller.


“There’s still a lot of development opportunity here,” Briggs said. “We have a vested interest in seeing the balance of the neighborhood built out in the right way. Whether we’re the developer or not remains to be seen.”

Casey Ross can be reached at cross@globe.com.