Somerville’s Union Square to see 2.3 million square feet of development

The Somerville Board of Aldermen voted 9-1 on June 12 to approve zoning changes necessary to the construction of a 2.3 million-square-foot development in Union Square around a future Green Line stop.

The $1 billion project, which developer US2 is overseeing, will include 1.38 million square feet of office, lab, retail, hotel, and arts space; and approximately 950 residences.

Twenty-five percent of the project is to be given over to public open space, including 2.5 acres of what US2 calls “high-quality civic spaces.”

And all of this is dropping near what will be the Union Square stop of the Green Line, which is supposed to open in 2021.

As for the development itself, construction on the first phase should commence in 2018 and wrap in 2020. That phase is due to include around 400 residential units and 175,000 square feet of either lab or office space as well as retail.

Construction of the whole shebang might take up to 20 years. Stay tuned.

• Green Line extension wins key federal approval for scaled-back version [Curbed Boston]