WASHINGTON — Democrats could get a major lift in their push for control of the U.S. House under the congressional map unveiled Monday by the Pennsylvania Supreme Court.

The new district map turns Pennsylvania from a state that sends 13 Republicans to Congress, against five Democrats, to one that would likely be close to evenly split, and  might produce a Democratic majority in a strong year for the left.

President Trump would have won 10 of the new districts while Hillary Clinton would have taken eight, if the redrawn boundaries had been in place in 2016. But several districts that Trump won handily would have been more competitive, including one in Northeast Pennsylvania, where a Democrat, Matt Cartwright, already holds the seat, according to several election analysts.

"Today's new map virtually ensures that Dems will at least draw even in PA; a good electoral climate pushes them into majority," tweeted Dave Hopkins, a Boston College political scientist.

GOP consultant Christopher Nicholas called the new map "a Dem wet dream."

Here are some key political takeaways from the proposal:

Southeast PA goes blue. One of the most dramatic shifts comes in the Philadelphia suburbs. The Delaware County-based seat currently held by retiring Republican Pat Meehan moves to a near-Democratic lock, according to David Wasserman of the Cook Political Report. A Chester County-based seat held by Republican Ryan Costello goes from a GOP lean to a strong Democratic opportunity — and his toughest declared competitor, Democrat Chrissy Houlahan, would remain in the district. (Republicans wanted to cut her out.) The Bucks County swing seat held by Republican Brian Fitzpatrick inches left, making it practically dead even.

Bottom line: In a Philadelphia region currently represented by three Democrats from the city and three Republicans in the suburbs, Democrats will be favored to land at least five seats, and maybe all six.

Philly loses a seat while Montco gains. Montgomery County scores a big win. The third most populous county in the state had been chopped up among several districts and had no home-county representative — but that changes with a new district centered in the heavily Democratic county.

Philadelphia drops from three hometown representatives to only two districts based in the city. (The district that is pushed out is represented by Democrat Rep. Bob Brady, who is retiring, so no incumbents would be tossed out.)

Delco dilemma. Delaware County might also become the base for a new Democratic representative.

But its new district is linked to a chunk of South Philly, creating the same dilemma there that left Montco without a home-county representative. If a large contingent of Delco Democratic candidates split the primary vote, they might open the door for a Philadelphian, similar to what happened when Rep. Brendan Boyle (D., Pa.) won in 2014 while facing three Montco competitors.

New competition. The map creates newly competitive districts all over the state. In some cases, strong GOP districts move within Democratic reach and some marginally competitive districts become nearly even.

A seat based in the Lehigh Valley, where Rep. Charlie Dent, a Republican, is retiring, shifts from a GOP-leaning district to one more balanced. A Republican district in Western Pennsylvania picks up a chunk of Allegheny County, giving Democrats a shot at winning a second seat in that region, instead of only one based in Pittsburgh. Rep. Scott Perry, a Republican from York County, sees more of Harrisburg and its surrounding area added to his district, making his safe seat more competitive.

Meanwhile, Republicans get almost no help in the one place where they stood to gain. Cartwright's Republican-leaning district is virtually unchanged in terms of partisan balance.

Smucker happy. Perhaps the one Republican who might feel better is Rep. Lloyd Smucker of Lancaster County. A top Democratic recruit, Christina Hartman, is challenging him and might have a shot if a wave materializes. But with all the shifting, his district grew much more Republican, likely keeping him safe — if this map holds.

Staff writers Holly Otterbein and Andrew Seidman contributed to this article.