LYNN – Eastern Bank acquired 44,000 new customer accounts over the Columbus Day weekend in a merger with MASSBANK.The deal marked Eastern Bank’s third merger in the past four years and gives the company nearly 90 branch locations and more than 100 ATMs across eastern Massachusetts.MASSBANK signs, fixtures and computer systems were converted to reflect the merger. Eastern Bank celebrated the event at its Chelmsford branch, where former professional quarterback Doug Flutie greeted new customers and hosted a passing contest.The merger was put into play on Sept. 3, when Eastern Bank acquired MASSBANK Corp. in a cash transaction valued at $170 million. The acquisition created a $7.1 billion commercial bank serving more than 500,000 consumers and businesses across eastern Massachusetts.Founded 190 years ago in Salem, Eastern Bank is now one of the largest mutually-owned banks in the country. Its customer service headquarters are located in Lynn.”We’re truly excited about the opportunity to serve consumers and businesses in these new communities and to demonstrate to them what ‘True Blue’ banking is all about,” said Richard E. Holbrook, Eastern Bank’s chairman and chief executive officer. “Eastern has a bright future.”According to Holbrook, in addition to the acquisition of MASSBANK, Eastern Bank is hiring new commercial and consumer bankers to assist with the transition of the new customers. Business hours at every branch will also remain unchanged.”Last month, we opened a new branch in Chelsea. In short, while mindful of the need to manage carefully during these turbulent economic times, we’re positioning ourselves for greater success in the years ahead,” he said.The Eastern Bank Charitable Foundation will soon distribute $50,000 in grant money to not-for-profit organizations headquartered in former MASSBANK communities. Nominated by the public over the last month, 20 organizations will each receive $2,500 donations made in honor of Eastern Banks’ merger with MASSBANK, reflecting Eastern’s commitment to the communities within its marketplace, according to bank spokesman Joseph Bartolotta.