Author’s Note: Other 2026 forecasts can be found in the Central File. This forecast/prediction contains proprietary mapping data beyond the paywall information prepared by the author for analytical purposes.
I. The Race
Scott Perry (Republican) is a retired Army brigadier general seeking his eighth term in the U.S. House. He was first elected in 2012 when the old boundaries of his district made up PA-4. In 2018, when the Pennsylvania Supreme Court issued a new map, his district was renamed PA-10 and was substantially more favorable for Democrats. Perry held on by a thread in 2024 despite Trump’s statewide victory.
Janelle Stelson (Democrat) is a former news anchor who narrowly lost to Perry in 2024. She touts her “former Republican” credentials to drum up moderate support and is running on a generic “affordability” platform. She has been extremely careful not to alienate Trump supporters, as opposed to the talking points of many of her Democrat counterparts running in 2026.
II. District Geography
Pennsylvania’s 10th Congressional District (PA-10) includes all of Dauphin County, which contains the state capital of Harrisburg, most of Cumberland County, and a portion of York County, which includes the York itself (the only favorable terrain Democrats have in York County).
Dauphin is relatively competitive for a capital county. Trump lost it by 2.9% in 2016, 8.5% in 2020, and 5.9% in 2024. Cumberland County is a GOP stronghold, but is starting to slip. Trump’s margin has gone from +17.8% in 2016 to just +9.4% in 2020. Trump has carried the present boundaries of PA-10 in all three of his runs, but the slippage is clear.
Presidential Margins
Key Statistics
71.2% White, 10.1% Black, 9.5% Hispanic
III. Market Assessment
Polymarket bettors, despite low volume, widely believe Stelson will pick up PA-10.
IV. History
The trail on PA-10 is hard to pick up thanks to the Pennsylvania Supreme Court overturning the map Perry ran on in 2016 when Trump first emerged at the top of the GOP ticket. Perry won the old PA-4 in a walk that year, topping his Democrat opponent by a margin of +32.2%. With the new map in place, things became much more difficult; Perry defeated Democrat George Scott by just 2.6%.
Surprisingly, Perry had little trouble holding the district in the fiasco that was Pennsylvania’s 2020 election, and slightly outran Trump. In 2022, he held the seat comfortably, beating Shamaine Daniels by 7.6% in a year the GOP retook the House majority:
Perry’s seat became hot (as it remains) in 2024, when he barely squeaked past Stelson in her political debut:
Perry’s margin was +1.2% (+5,133), underperforming Trump’s margin in PA-10 by a full four points. The recent history of PA-10 paints one of the few rosy pictures in Pennsylvania for Democrats.
V. Analysis of 2026 Primary Results
Perry ran unopposed in the GOP primary. Stelson took on a challenge from the left by Justin Douglas, a woke Dauphin County Commissioner who somehow thought it was a good idea to run on abolishing ICE in a state that is 12 points right of its 2008 presidential margin. Stelson prevailed roughly two-to-one: