DOVER — Lisa Blunt Rochester spent nearly $1.4 million to win the state’s open seat in the U.S. House of Representatives, data from the Federal Election Commission shows.

Rep.-elect Blunt Rochester, a Democrat, won a crowded primary and then topped Republican Hans Reigle and two minor-party candidates to become the state’s next member of Congress. It was her first bid for elected office.

Aided by a self-loan of $464,500, Rep.-elect Blunt Rochester pulled in $1.55 million from October 2015 to November 2016. A former state labor secretary, she received 56 percent of the vote last month.

Mr. Reigle, who earned 41 percent of the votes, raised $222,000, spending all but about $3,000.

WOMEN VOTE!, a political action arm of EMILY’s List, spent $178,000 in behalf of Rep.-elect Blunt Rochester before the primary. EMILY’s List is a group that works to get Democratic women who are pro-choice on abortion elected.

The new congresswoman paid out just over $500,000 to The Campaign Group, a Philadelphia firm that crafts ads for Democratic candidates. All but $177,000 of her spending came before the Sept. 13 primary election.

The second-place finisher in that hotly contested primary, state Sen. Bryan Townsend, raised $769,000 and spent $757,000 from September 2015 to September 2016.

Sean Barney, the Democrats’ 2014 state treasurer nominee, raised $772,000 and spent all but $1,000 of it. He was supported by the action fund of VoteVets.org, a group that backs left-leaning candidates who served in Afghanistan and Iraq.

The organization spent $192,000 advocating for Mr. Barney before the primary.

State Rep. Bryon Short, a Democrat who dropped out of the race in April, picked up $236,000 and spent $210,000.

Data for other candidates was not available, likely indicating they did not spend or raise more than $5,000.