On July 15, 2013, Ed Markey resigned from the seat to become the junior Senator from Massachusetts.

On December 10, 2013, Democrat Katherine Clark won a special election to fill the seat for the remainder of the 113th Congress.

Before Paul Tsongas' victory that year, it had only elected three Democrats in its entire existence and had been in Republican hands since 1895.

In state races, it supported Republican candidates for Governor William Weld, Paul Celluci, and Mitt Romney.

In the 2007 special election to replace Marty Meehan, Republican candidate Jim Ogonowski ran an unexpectedly strong race before ultimately losing, 51–45%.