PA-10 · House

The district, in brief

Pennsylvania's 10th district is based in the Harrisburg and York areas, including all of Dauphin County, most of Cumberland County, and the northern half of York County. The lines are unchanged for 2026; the facts record the map as first used in 2022.

The incumbent is Republican Scott Perry, re-elected with 50.6% of the vote in 2024 and unopposed in the Republican primary. The Democratic nominee is Janelle Stelson, a former WGAL news anchor and the party's nominee for this district in 2024, who won the Democratic primary with 67.4% over Justin Douglas, a Dauphin County commissioner since 2023 who later endorsed her. Isabelle Harman declared as an independent but did not file. As of June 30, 2026 Perry had raised $5,194,925 with $2,845,976 on hand; Stelson had raised $6,364,069 with $4,478,639 on hand.

Decision Desk HQ (August 7, 2026) and Silver Bulletin (August 20, 2026) rate the seat Flip; the Cook Political Report (September 11, 2025), Inside Elections (May 21, 2026) and Sabato's Crystal Ball (April 10, 2025) rate it Tossup. Four district polls are recorded, each with Stelson ahead: Franklin & Marshall College (September 9–20, 2026) 47%–44%; Normington Petts, a Democratic firm (April 20–23, 2026), 51%–45%; Public Policy Polling for Republicans Against Perry (November 18–19, 2025) 48%–44%; and Public Policy Polling (July 10–11, 2025) 46%–43%.

A paragraph quoting a model forecast from the day this brief was written is omitted; the current forecast is at the top of this page.

The facts, each beside its sentence

Not in the source: The text gives no presidential results for the district; the facts carry a 2024 presidential baseline on the current lines.; The model's basis says no district polls, but the text carries four polls that are not in the project's poll corpus.; The endorsements and post-primary endorsements sections are empty.; The text does not say why Karen Lynn Dalton was nonqualifying, or whether Perry drew any primary opponent on the ballot.

Read from the district's section of Wikipedia's state page (CC BY-SA), archived as 716a870fb99d; written by claude-fable-5-1 (batch reader) on 2026-09-30 and checked mechanically: every quote occurs verbatim in the archived text, every number in the brief occurs in the inputs. No probability here is the reader's.

Who holds the seat now

Scott Perry (Republican), in this chamber since 2013, 7 terms. Committees: House Committee on Transportation and Infrastructure; House Committee on Oversight and Government Reform; House Permanent Select Committee on Intelligence; House Committee on Foreign Affairs.

From the congress-legislators dataset (CC0), archived as ae8cb9477c48. For a Senate race this lists both of the state's senators; the one whose term ends in the election year holds the seat on the ballot. For a House district redrawn for 2026 it is the member elected under the old lines with this number, who may be running elsewhere; the dossier above names who is running here.

How it has voted for president

A shift of 5.2 points toward the Democrats from 2016 to 2024. county returns placed on the current lines by 2020 block population; MEDSL county file (2016), an MIT-licensed county file (2020, checked against certified state results) and MEDSL precinct returns (2024). For a district split across counties this is an estimate, and where the state published the exact 2024 figure for these lines, that exact figure is the one the model uses.

Who are the voters?

Of about 533,157 adults 25 and over. In 2020 the district voted 47.9% Democratic (two-party) for president. With the same preferences and a 2022-style midterm turnout, it would vote 48.9% Democratic: the midterm electorate alone moves the margin 2.0 points toward Democrats. Group shares are estimated from how results vary across the state's census tracts (ecological inference, anchored to Pew's 2020 validated-voter figures) and calibrated to this district's actual 2020 vote; turnout is the Census survey's state rate by race and national rate by education, whose state samples carry margins of several points.

Not answered here: how each group will vote in 2026. These are 2020 preferences; this profile is description, not yet an input to the forecast.

The money

FEC bulk candidate summaries through July 16, 2026; $313,020 of independent expenditures for or against these candidates this cycle (FEC Schedule E, types 24E and 24A), which is the parties' and outside groups' own revealed view of whether this seat is in play.

The district in numbers

ACS 5-year 2023, the Census Bureau's own tabulation of this district (118th Congress lines). Unemployment is the BLS county series placed on the district by block population, not seasonally adjusted, so changes are same-month comparisons. Income, transfers and jobs are BEA county accounts placed the same way, compared with the average district. Every other figure is a named column of a named table in the Bureau's summary file, archived before it was read. This is what a reader knows about a district before looking at a poll; the model does not yet use it, and whether it should is a registered question.

Who is favoured, and by how much?

The 90% interval runs from -14.3 to +13.5 points, D-R. It is wide because this district has never been polled.

What is this built on?

A model trained on every contested House race 2012-2024 predicts this district's lean from its own record: presidential and House results on the current lines, incumbency, both candidates' prior offices, outside and party money before 1 October, demographics and public-assistance shares from the Census release before the election, local unemployment and income, and religious tradition. The national margin comes from presidential approval, the economy, the midterm penalty and the generic ballot corrected for its measured lean. Draws share national and state errors, so the seat total and this district come from the same simulation.

Not answered here: district polls, which are not yet folded in.

Why does the model say this?

Each figure is how far this district's predicted lean moves when that one feature is set to the typical value across 2026 districts, everything else held: outside money balance: 3.0 pts toward the Democrat; experience gap (-4 levels, D minus R): 2.1 pts toward the Republican; religion: mainline (12.1%): 0.9 pts toward the Democrat; asian share (4.9%): 0.7 pts toward the Democrat; total outside/party money: 0.4 pts toward the Democrat.

How sure is it, and of what?

Total sd 8.42 points, made of the seat's own volatility 89%, correlated polling error 11%. The decomposition is stored with the forecast rather than reconstructed, so a probability whose dominant input is a placeholder is visibly that.

Not answered here: a nowcast. 'If ballots were cast today' needs something that observes today, and for a House district nothing does. Publishing the election-day figure under both labels would make one forecast look like two.

How was this number made?

Run 0b33151b-a949-47f1-b845-564833a2b74d, house_district_prior/0.2.0, as of 2026-10-02. Promoted by a pre-registered gate: on 2016-2022 its Brier score was 0.036 against 0.049 for the previous method, and on a single 2024 run 0.023 against 0.032 (experiments/district_gate_result.md, with an independent review).