On the night of the election, all nine races were declared in favor of the Democratic Party candidates.

[1] Seven seats went to incumbents seeking re-election: Richard Neal (1st District), Jim McGovern (2nd), Joseph Kennedy III (4th), Katherine Clark (5th), Seth Moulton (6th), Stephen F. Lynch (8th), and Bill Keating (9th).

In the 7th District, Ayanna Pressley ran unopposed after defeating the incumbent in the primary election.

In the 3rd District, where the incumbent did not seek re-election, Lori Trahan was declared the winner.

[2] Results of the 2018 United States House of Representatives elections in Massachusetts by district:[3] Richard Neal Democratic Richard Neal Democratic The 1st congressional district is located in western and Central Massachusetts.

The largest Massachusetts district in area, it covers about 1/3 of the state and is more rural than the rest.

For the fourth election cycle in a row, no Republicans filed to run in this district.

[5] Lori Trahan and Daniel Koh were separated by less than one half of one percent of the votes cast.

The incumbent was Democrat Katherine Clark, who had represented the district since winning a special election in 2013.

[47][48][49][50][51] John Hugo was certified to appear on the ballot for the 2018 elections on May 17, 2018, to run against Katherine Clark.

In his bid for re-nomination by the Democratic Party, Capuano was defeated by Boston city councillor Ayanna Pressley.

[54] The primary victory was a surprise,[55] as the last poll before the election showed Capuano with a significant lead, 48% to 35%.

[56] Part of the reason the polls may have been inaccurate was a surge in the number of primary voters.

Two political newcomers ran against Lynch in the primary, video game developer Brianna Wu and pilot Christopher Voehl.

Bill Cimbrelo, a businessman and former environmental chemist from Osterville, announced that he planned to challenge Keating in the September primary.