Two prominent Boston law firms, 340-lawyer Edwards & Angell and 180-lawyer Palmer & Dodge, today announced that they will merge, effective Nov. 1. The combined firm, Edwards Angell Palmer & Dodge, will have 520 attorneys, nine offices and 20-plus practice areas in the United States.

“We believe our increased size and depth will be a platform for growth, giving us a competitive edge that will allow us to continue to attract the best lawyers, clients and work,” Charles DeWitt, managing partner of Palmer & Dodge, said in a statement announcing the merger. DeWitt will become co-managing partner of the new firm, along with Terrence Finn, managing partner of Edwards & Angell. Both will be based in Boston.

Edwards & Angell has offices in Boston; New York; Providence, R.I.; Hartford and Stamford, Conn.; Short Hills, N.J.; Fort Lauderdale and West Palm Beach, Fla.; and Wilmington, Del. Its focus is financial services, private equity, venture capital and technology. Boston-based Palmer & Dodge has become known in recent years for its representation of life sciences and technology companies.

In 2000, Edwards & Angell merged with the intellectual property firm Dike Bronstein Roberts & Cushman.