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Allegheny County, PA
How Atlas thought about thisplace_lookup

Question interpretation

Profile of Allegheny County, Pennsylvania — presidential margin history, demographics, and national/state context.

Resolution strategy

  1. 01lookup_geographyallegheny
    Parameters
    {
      "query": "Allegheny County, PA",
      "preferred_geo_types": [
        "county"
      ]
    }

Plus 2 comparison shapes: containing_state, national.

Data pulls

  • reaggregationallegheny · 2024, 2020, 2016, 2012, 2008
  • demographicsallegheny
  • historyallegheny · 2024, 2020, 2016, 2012, 2008
  • forecastallegheny

Sections

  1. 01
    overview
  2. 02
    shape_map
  3. 03
    historical_trend
  4. 04
    demographic_lens
  5. 05
    comparison_table

Narrative angle

Headline emphasis. 2024 partisan margin and the trajectory since 2008

Frame. Pittsburgh-anchored urban county in a battleground state with a specific cycle-by-cycle arc.

View raw JSON
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  "sections": [
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      "depends_on": [
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      "shape_label": "allegheny"
    },
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      "shape_label": "allegheny"
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      "Speculation about causes of partisan shifts without data"
    ],
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  },
  "resolution_strategy": {
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        "tool": "lookup_geography",
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          "query": "Allegheny County, PA",
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  "confidence_rationale": "Named county, high-coverage state, direct MV lookup path with full five-cycle history available.",
  "question_interpretation": {
    "summary": "Profile of Allegheny County, Pennsylvania — presidential margin history, demographics, and national/state context.",
    "ambiguity_notes": [],
    "question_archetype": "place_lookup"
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}
  1. Plan drafted
  2. Shape resolved — allegheny
  3. Section 2 · overview
  4. Section 3 · shape_map
  5. Section 4 · historical_trend
  6. Section 5 · demographic_lens
  7. Section 6 · comparison_table
Answer readycached

Pittsburgh-anchored urban county in a battleground state with a specific cycle-by-cycle arc.

Scroll to read the full answer

Pittsburgh-anchored urban county in a battleground state with a specific cycle-by-cycle arc.

from cache$2.4266s
overview02
D+20.3
Lean Score
D+19.8
2020 margin
D+20.4
2024 turnout
74.2%

D+20.3 in 2024 for Allegheny, essentially flat from D+20.4 in 2020. 1.24M people anchor Pittsburgh's urban core, with a lean score of D+19.8. Turnout reached 74.2%.

high confidence
shape map03
Primary shape
Allegheny
Comparison outlines
3 · PA
Center
40.46°N, 79.92°W
Zoom
z8
Extent
0.67° × 0.48°

Allegheny County, anchoring southwestern Pennsylvania around Pittsburgh.

historical trend04

Shifted 4.9 pts right across 16 years.

DR20202008: D+15.42012: D+14.52016: D+16.42020: D+20.42024: D+20.320082024
D+15.4 in 2008, D+20.3 in 2024, shifted 4.9 points right; inflection at 2020.
2008D+15.42012D+14.52016D+16.42020D+20.42024D+20.3

Allegheny shifted 4.9 points left from 2008 to 2024, ending at D+20.3. The biggest single-cycle move came in 2020, when margin widened from D+16.5 to D+20.4, and 2024 held nearly flat at D+20.3. Turnout peaked at 724,800 in 2020 before easing to 720,504 in 2024.

demographic lens05
race composition
white 76.1%Black 12.5%Hispanic 3.0%Asian 4.4%

No comparison geography available.

population
1,238,177
voting-age population
971,548
non-Hispanic white (approx.)
73.1%
median household income
$78,548
bachelor's+
45.8%
poverty rate
11.5%
foreign-born
6.6%
  • Direct lookup at county geo_id county:2020:42003.
  • pct_non_hispanic_white is approximate: computed as (pop_white - pop_hispanic) / total_population. PL 94-171 race/ethnicity cross-tabs are not available at block-group resolution.
  • median_age not aggregated at block-group level in v1; returned null.
  • No containing-geography race breakdown available; contrasting_dimension omitted.

Plurality white at 76.1% (73.1% non-Hispanic white), 1.24M people. 45.8% of adults hold a bachelor's degree, with median household income at $78,548. Black residents make up 12.5% and foreign-born share sits at 6.6%.

comparison table06
  • Allegheny+4.9 pts
    2016
    D+16.4
    2020
    D+20.4
    2024
    D+20.3
  • Pennsylvania-1.0 pts
    2016
    R+0.7
    2020
    D+1.2
    2024
    R+1.7
  • PA-12+1.6 pts
    2016
    D+17.5
    2020
    D+19.9
    2024
    D+19.1

Pennsylvania is the outlier, running R+1.7 in 2024 while Allegheny County posted D+20.3 and PA-12 came in D+19.1. The state sits roughly 22 points to the right of both Allegheny and its anchoring district. Allegheny and PA-12 tracked within 1.2 points of each other in 2024, 0.5 points in 2020, and 1.0 point in 2016.