While much of the conversation and analysis surrounding congressional districts references the presidential results, there’s another, more comprehensive metric.
Inside Elections’ Baseline captures a congressional district’s political performance by combining all federal and state election results over the past four election cycles into a single score. This index aims to approximate what share of the vote a “typical” Democrat or Republican might receive in any given district.
There are 10 districts where one party has a Baseline advantage of a point or less, and each party represents five of those 10 districts. With Republicans clinging to a narrow House majority, every seat is going to matter as Democrats try to gain the three seats they need for a majority.
Overall, there are 215 Districts where Republicans have a Baseline advantage compared to 220 where Democrats have a Baseline advantage, before the Texas changes are made official.
With mid-decade redistricting, there is some fluidity to the list.
The newly-drawn Texas’ 34th District , currently represented by Democratic Rep. Vicente Gonzalez , might be included with a D+1 Baseline.
If voters pass the Democratic-drawn map in California , the Democratic-held 13th and 45th will drop off while GOP Rep. Darrell Issa’s 48th will be added.
Utah may have a newly-drawn, very competitive district. And Ohio’s 13th District , represented by Democratic Rep. Emilia Sykes , sits just outside the closest 10, but could get added after Republicans redraw the Buckeye State .
Here is the initial list of 10 most-evenly divided districts.
California’s 13th District
The most evenly-divided seat in the country may not even exist for the 2026 midterm elections.
According to Inside Elections’ Baseline, Republicans have a 49.9-49.8 percent edge, coming out to an R+0.1 in the Central Valley seat. The district is currently represented by Democrat Adam Gray . But Democrats redrew the district to be significantly more Democratic (D+7) and if the map passes in November, this seat will fall off the list. If the map is defeated, it’s hard to imagine a seat getting much closer than this one.
Arizona’s 6th District
If California has a new map, this Arizona district could become the most evenly-divided, making it a challenge for GOP Rep. Juan Ciscomani to win another term. Democrats have a 49.8-49.5 percent (D+0.2) Baseline advantage in the southeastern Arizona seat. Marine drill instructor Jo Mendoza is the Democratic frontrunner.
North Carolina’s 1st District
Democratic Rep. Don Davis survived in 2024 but will continue to be a target based on the nature of his inland northeastern district, where Democrats have a 50.0-49.5 percent (D+0.5) Baseline advantage. Republicans are hoping to avoid a messy primary, with Rocky Mount Mayor Sandy Roberson as the early frontrunner.
Pennsylvania’s 8th District
Republicans have a narrow 49.2-48.6 percent (R+0.6) Baseline advantage in this northeastern Pennsylvania seat. GOP Rep. Rob Bresnahan Jr . is up for reelection after defeating Democratic Rep. Matt Cartwright by a point and a half in 2024. Scranton Mayor Paige Cognetti is seriously considering a run and is the type of challenger Democrats are looking for in a top-tier opportunity.
Washington’s 8th District
Democratic Rep. Kim Schrier represents one of the most evenly-divided districts in the country, but it has confounded Republicans . According to Baseline, Democrats have a narrow 50.1-49.5 percent (D+0.6) advantage and yet there hasn’t been any buzz about the race from Republicans in at least a couple years. Schrier won by 8 points in 2024 and Republicans are searching for a candidate once again.
California’s 45th District
Democratic Rep. Derek Tran currently represents one of the most-evenly divided districts in the country, but Gov. Gavin Newsom is hoping voters will agree with his changes to the lines. Right now, Democrats have a 50.1-49.6 percent Baseline edge in this Southern California seat. But the performance of the seat would change from D+0.6 to D+5 if the map passes this November and Tran would be in much better shape.
Nebraska’s 2nd District
GOP Rep. Don Bacon’s decision not to seek reelection makes this a very difficult open seat for Republicans to hold. Democrats have a narrow 49.9-49.1 percent (D+0.8) Baseline advantage in this Omaha -anchored district and Kamala Harris finished ahead of President Donald Trump in the presidential race. Both parties are facing primaries ahead of a competitive general election.
Iowa’s 3rd District
GOP Rep. Zach Nunn isn’t even the most vulnerable Republican in Iowa , but he doesn’t have as much of a buffer as his colleague Mariannette Miller-Meeks . Nunn’s district has a narrow Democratic edge, 49.6-48.7 percent, (D+0.9), according to Baseline. Republicans had to make sure Nunn didn’t run statewide because he’s probably their best chance of holding the seat. Democrats have a competitive primary before focusing on the congressman.
New Hampshire’s 1st District
Democratic Rep. Chris Pappas hasn’t had much trouble winning this seat, but now that he’s running for the Senate, Democrats can’t take the open seat for granted. Republicans have a narrow 49.9-48.9 (R+1) Baseline advantage in the seat that takes in the eastern part of the state. Stefany Shaheen might have the slight edge on the Democratic side, but Maura Sullivan and others are running as well. On the Republican side, state Rep. Brian Cole and 2024 candidate Chris Bright are running, but the field is still taking shape.
Pennsylvania’s 7th District
Republican Ryan Mackenzie knocked off Democratic Rep. Susan Wild by a point in 2024 and is trying to win reelection in this Lehigh Valley seat where Democrats have a narrow (D+1) Baseline advantage, 49.4-48.4 percent. Democrats have to sort through a competitive primary but could have the national political environment in their favor as well as boost from Democratic Gov. Josh Shapiro at the top of the ticket.
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