Medfield-based Delta Real Estate has affiliated with William Raveis, and will be renamed William Raveis Delta Realtors. The merger expands the number of Massachusetts offices for Raveis to 30.

 "As we continue to grow the affiliate’s component of William Raveis in Massachusetts, Medfield has always been a target," Chris Raveis, managing partner of William Raveis Massachusetts, in a statement. "Delta Real Estate is a well-established, and well-respected, part of their local community. Their team is extremely knowledgeable about the area, and that knowledge will be vital as we expand our presence in the Medfield market."

Over the past 10 years, William Raveis has expanded from its home state of Connecticut, operating 44 offices in Massachusetts, New York and Rhode Island.

"William Raveis has an impressive history, and their growth in Massachusetts over the past decade made them stand out among other real estate companies," Ralph Costello, broker owner of William Raveis Delta Realtors, said in a statement. "I look forward to growing our market share while being associated with a company with a longstanding track record of success."

Delta Real Estate also operates a home building subsidiary, Unique Homes, which specialized in historic preservation. Delta was recognized in 1995 by the town of Medfield Historical Commission for its preservation of historical buildings and trails at "The Preserve at Kingsbury Pond," a project of six custom homes clustered on 25 acres with antique barns and structures, now part of the Clark-Kingsbury Farm Historic District. The firm’s Olde Village Square project, a 42-unit condominium development, was recognized by The Builders Association of Greater Boston as the best multifamily project in Greater Boston in 2009.