Construction of the newest office tower in the Innovation District begins this week.

A groundbreaking ceremony was scheduled for Wednesday for a 500,000-square-foot office tower anchored by law firm Goodwin Procter LLP and developed by The Fallon Co. of Boston.

Goodwin Procter agreed in 2012 to move to the planned 17-story tower at 100 Northern Ave. from its longtime 53 State St. headquarters in the Financial District. The new location will house more than 800 employees.

The law firm will occupy 375,000 square feet on 12 floors, with a projected move-in date in the summer of 2016. The lease term is 15 years.

Developer Joseph Fallon said the company is negotiating with other law firms, venture capital firms and tech companies to fill the rest of the building.

"We’ve seen great interest both from downtown tenants and from the 128 belt," Fallon said.

The Fallon Co. also is in final negotiations with retailers for ground-floor space.

"This new building reaffirms our commitment to a thriving city and a vibrant new neighborhood that is attracting innovative companies across many sectors," said Goodwin Procter Chairman Regina M. Pisa in a statement.

The firm has hired Bargmann Hendrie + Archtype Inc. of Boston to serve as interior architects.

The Fallon Co. is the developer of the 21-acre Fan Pier project on the South Boston waterfront, including the 1.1-million-square-foot Vertex Pharmaceuticals headquarters that opened in early February. In 2009, it completed One Marina Park Drive, the first major new office tower in the current development boom in the Seaport District. In October, it broke ground on 22 Liberty, a 14-story luxury condo complex with 118 units.

Email: sadams@thewarrengroup.com