The construction of the new headquarters of the Maryland housing agency in New Carrollton is a step closer.

The Prince George’s County Planning Board on Thursday unanimously approved key elements of the project, allowing the developer to move forward with the grading and permitting process.

In May, a state board approved the relocation of the Maryland Department of Housing and Community Development, and its nearly 400 employees, from its current Anne Arundel County location to Prince George’s. The decision, although protested by Anne Arundel County officials and some agency workers, was an important victory for Prince George’s.

The county sees the move as a significant boost to its economic development efforts and officials say the construction of the state housing department headquarters on the 26-acre site near the Metro station will provide a model for developers considering transit-oriented sites in Prince George’s.

The state agency will anchor a large new development in New Carrollton, just steps from the New Carrollton Metro Station. The site is in a major transit hub with access to MARC, Amtrak and local and regional bus lines. The easternmost stop, the future light-rail Purple Line, will be built in New Carrollton.

The planning board onThursday vote moved forward the first phase of the plan, which calls for the construction of 556 residential units and 200,000 square feet of office and retail spaces. The developer plans to build a mix of studio, 1 and 2 bedroom apartments units in a community with amenities that include a swimming pool and a gym.

Kevin Berman, a developer with Berman Enterprises, said the developing team is moving to keep up with the scheduled opening of the new building in June 2015. When built, the housing department will be the first state agency based in Prince George’s.

“We are pushing ahead,” Berman said after the planning board vote Thursday afternoon.

A second phase will add up to 2,400 residential units, 100,000 square feet of retail and a 300-room hotel, the developer said.

County officials say they also hope the development will drive a transformation outside the New Carrollton Metro, from a place now mostly surrounded by empty parking lots and some office buildings, into a vibrant urban center.