Reed, in office since 2003 and majority leader for three years, would face a crowded Republican Party primary in the solidly Republican 9th District, where Donald Trump won 70 percent of the vote for president.
Arnold McClure, the Huntingdon County Republican Party chairman, said Reed called him this week to tell him of his plans.
"Dave Reed is running in the 9th District," McClure said Thursday.
Two other Republican Party officials also said Reed informed them of his plans to announce his candidacy. They said they would speak to The Associated Press only on the condition of anonymity because Reed wants to make a formal announcement next week. Reed, of Indiana County, was expected to do that Monday.
In an email Thursday, Reed, 39, said his family will make a decision over the weekend on whether he should run for Congress or his state House seat "and announce the path forward next week."
Other Republicans running in the 9th District include third-term state Sen. John Eichelberger and Art Halvorson, a Coast Guard veteran and a tea party-backed conservative who lost narrowly to Shuster in 2016.
The primary election is May 15. The deadline to file paperwork to get on the ballot is March 6.
Schuster said this month that he would not seek another term in the seat he has held since 2001 after taking it over from his father. The 9th District, in the southwestern part of the state, spans all or parts of 12 counties and includes Altoona, Chambersburg and Uniontown.
Reed's departure from the House could set off a reshuffling in GOP leadership ranks after three years of battling Democratic Gov. Tom Wolf, including two protracted budget stalemates. House Speaker Mike Turzai, R-Allegheny, also could depart.
Turzai has announced his candidacy for governor, although he has given up on plans to run for higher office twice before and still plans to run for his House seat.
Primary fields for Pennsylvania's 18 U.S. House seats could be jam-packed this year, driven by Democrats' anti-Trump fervor and a rush to fill the most open seats in the state in decades. More than 60 people, including 14 sitting U.S. House members, are either committed to running or are considering it, even as the state Supreme Court considers a gerrymandering lawsuit seeking to throw out those boundaries.
Thirteen candidates have lined up in eastern Pennsylvania's closely divided 15th District, where Republican U.S. Rep. Charlie Dent won't seek another term. The latest is Republican Dan David, a hedge fund manager. By spring, the first-time candidate may be better known as a featured face in "The China Hustle," a documentary film about fraud by Chinese firms that get listed on U.S. stock exchanges.
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