Pittsfield-based Berkshire Hills Bancorp Inc. has acquired Pittsfield’s Legacy Bancorp Inc. for $108 million, under which Berkshire will acquire Legacy and its subsidiary, Legacy Banks.

The combined institution will boast $4 billion in assets, according to a statement. Legacy has $1 billion in assets and 19 branches, and Berkshire has $3 billion in assets and will have 47 branches, including the branches of New York-based Rome Bancorp, which Berkshire is acquiring in a separate, pending deal.

"This in-market combination will create a strong platform headquartered in Berkshire County for further growth of our Northeast regional franchise," Michael P. Daly, Berkshire’s president and CEO, who is expected to take charge of the new entity, said in a statement. "I look forward to welcoming the Legacy team into the culture …. as we together provide the best financial support and solutions to our markets."

"Legacy and Berkshire have been friendly competitors over the years, and now we’re joining the Berkshire team to create a larger combined platform to serve our traditional and target markets," said J. Williar Dunlaevy, a Legacy board director. "This transaction produces a very attractive immediate return to our shareholders."

Dunlaevy added: "As we considered our strategic alternatives, there were compelling reasons for us to seek this partnership with Berkshire. Berkshire is a company with strong momentum and is well positioned as a bank that knows our communities, understands the customers we serve and offers a unique brand promise for customer engagement. I look forward to joining the Berkshire executive team, and to successfully integrating our neighboring operations and accelerating our combined earnings growth in New England and New York."

The merger is expected to be completed in June 2011.