Ballotpedia is tracking U.S. House races without a known Democratic or Republican candidate in the 2020 elections. As of April 15, 25 states have U.S. House races without a major-party candidate. A total of 26 U.S. House races do not have a Democratic candidate, and 31 do not have a Republican candidate.

The most seats without a candidate from one of the major parties are concentrated in two states: Massachusetts and New York. Massachusetts has the highest number; of its nine congressional districts, eight do not have a Republican candidate. New York has the second-highest with five of its 27 districts having no Republican in the race. Louisiana has the most races without a Democratic candidate with four across its six districts.

In 2018, 41 of the 435 U.S. House races lacked either a Democratic or Republican candidate in the general election. Three of the 41 races did not have a Democratic candidate on the ballot, and the remaining 38 did not have a Republican candidate running. In comparison, there were 61 such seats in 2016 and 76 in 2014.

During the 2020 election cycle, the filing deadline to run for federal office has passed in 34 states. Michigan has the next filing deadline on April 21.

Additional reading:
United States House of Representatives elections, 2020
U.S. House elections without a Democratic or Republican candidate, 1920-2018