Congressional Voting Data

Party Vote Share Over Time

Aggregate congressional vote percentage by party across all Maryland districts.

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Chart will appear once data is compiled

See methodology below

Why Congressional Vote Share Matters

When analyzing redistricting and gerrymandering, seat counts don't tell the whole story. A party could win 60% of the votes but only 50% of the seats—or vice versa. This gap between votes and representation is a key indicator of how fairly district lines are drawn.

Vote Share

The actual percentage of votes each party receives across all districts. This reflects true voter preferences.

Seat Share

The percentage of congressional seats each party wins. This can be manipulated through gerrymandering.

By tracking aggregate vote totals across all Maryland congressional races since 1922, we can see the long-term partisan preference of Maryland voters independent of how district lines were drawn in any given decade.

Methodology

What We're Measuring

For each general election year (every two years), we calculate:

Total Democratic Votes: Sum of all votes for Democratic candidates across all MD congressional districts
Total Republican Votes: Sum of all votes for Republican candidates across all MD congressional districts
Other Votes: Third party, independent, and write-in candidates
Vote Percentages: Each party's share of the total vote

Data Sources

U.S. House of Representatives Election Statistics

Official vote counts collected by the Clerk of the House since 1920

history.house.gov/Institution/Election-Statistics →

Format: PDF files per election year, requires manual extraction

Maryland State Board of Elections

Official state election results with precinct-level detail

elections.maryland.gov →

Coverage: 2000-present, some years have CSV downloads

Important Notes

We include all votes cast, not just votes for winners
Uncontested races use actual vote totals (we don't impute missing opponents)
Special elections are excluded—only regular November general elections
Write-in votes are counted in "Other" when reported
Maryland's number of districts has changed: 6 (1922-1952), 7 (1952-1962), 8 (1962-present)

How to Help Compile This Data

We're looking for volunteers to help extract data from the official sources. Here's the process:

1

Download the PDF

Go to the House.gov election statistics page and download the PDF for your chosen year

2

Find Maryland Results

Locate the Maryland section with results for all congressional districts

3

Sum the Votes

Add up all Democratic votes across all districts, then all Republican votes, then other

4

Submit via GitHub

Open an issue or PR with the year, vote totals, and source page numbers

Example Data Format

{
  year: 2022,
  democraticVotes: 1234567,
  republicanVotes: 876543,
  otherVotes: 12345,
  source: "House.gov 2022 Election Statistics, pages 45-48"
}

Election Data Status

Tracking progress on data compilation for each election year.

Year	Districts	Dem %	Rep %	Status	Notes
Loading election data...

API Endpoints

Access this data programmatically via our API.

GET /api/elections

Get summary of all elections with percentages

GET /api/elections/full

Get full election data including raw vote counts

GET /api/election/{year}

Get data for a specific election year

GET /api/elections/decade/{decade}

Get elections by decade (e.g., 1990, 2000, 2010)

GET /api/elections/methodology

Get methodology and data source information