Eastern Bank is the largest independent, mutually owned bank in New England and the largest community bank in Massachusetts. With 82 branches, Eastern has a 2.83% market share in Massachusetts as of 2009. Founded in 1818 and originally based in Salem and then Lynn, Massachusetts, the company began an aggressive expansion campaign near the end of the 1990s and moved its headquarters to Boston's Financial District.

Eastern Bank was established on April 15, 1818 as Salem Savings Bank and became FDIC insured on October 1, 1983. On October 19, 1989, Eastern Savings Bank's parent company Lynn, Massachusetts-based Eastern Bank Corporation, renamed it Eastern Bank, while also reorganizing it into a mutual holding company, making it the first of its kind in Massachusetts.

In the years following its reorganization, it made several acquisitions of local banks. They included Shore Bank And Trust Company (Lynn, April 1992), Malden Trust Company (Malden, May 1992), First Colonial Bank For Savings (Lynn, October 1993), and Saugus Bank And Trust Company (Saugus, November 1994).