Federal-Court Validated · All 50 States · 2010 & 2020
Built on the Census Bureau's PL 94-171 Redistricting Data and CVAP Special Tabulation. Population-weighted block interpolation. Validated against federal litigation standards. Thirteen race and ethnicity categories per voting tabulation district.
Any-Part Black CVAP — Alabama 2020, Voting Tabulation Districts
Platform Capabilities
Every precinct in the United States. Voting-age population from the official redistricting files. Citizen voting-age population interpolated to the precinct level. Fully downloadable. Court-ready.
Total population, voting-age population (18+), and race/ethnicity breakdown across nine categories for every voting tabulation district in the United States. Drawn directly from the Census Bureau's official redistricting files — the same source every redistricting plan must use. Both 2010 and 2020 decennial cycles available for side-by-side comparison.
The Census Bureau publishes CVAP only at the block-group level — the finest geography available. This platform uses population-weighted block disaggregation to produce CVAP estimates for every precinct. Thirteen categories including Any-Part Black and Hispanic or Latino CVAP. Period-matched vintages: 2016–2020 ACS for 2020 precincts; 2006–2010 ACS for 2010 precincts.
Racially polarized voting analysis requires election returns merged to VTD-level VAP. Effectiveness analysis requires the ratio of minority CVAP to total CVAP within a proposed district. This platform provides both the VAP numerator for RPV and the CVAP numerator and denominator for effectiveness — at the VTD level — enabling direct computation of minority citizen voting-age share for any precinct configuration.
Methodology
Block-group CVAP from the ACS 5-year Special Tabulation is disaggregated to individual Census blocks using each block's share of the block-group's total voting-age population as the interpolation weight:
w(b) = VAP(b) / Σ VAP(b') for b' ∈ BlockGroup
CVAP̂(b) = CVAP(bg) × w(b)
CVAP̂(vtd) = Σ CVAP̂(b) for b ∈ VTD
Block-level estimates are summed to VTDs via the Census Bureau's Block Assignment Files. For 2010 data, 2010 block geography is matched with 2006–2010 ACS CVAP. For 2020 data, 2020 block geography is matched with 2016–2020 ACS CVAP. Cross-decade analysis uses the Census Bureau's Block Relationship Files to align 2010 VTD estimates to 2020 geographies by land-area weight.
Data Access
No login required for the state explorer. Download full state-level CSVs directly. All data is drawn from public Census Bureau sources and is free to use.
Select a state, choose a demographic metric — Total CVAP, Black Alone CVAP, Any-Part Black CVAP, Hispanic CVAP, and more — then select 2010 or 2020. Instantly visualize a bubble map of VTD-level concentrations with hover tooltips, a sortable precinct table, and one-click CSV download. CVAP and VAP metrics available side by side.
Open CVAP State ExplorerZoom into a single county for higher map resolution. Essential for single-member district analysis in majority-minority litigation, where the relevant geography is often a single county or metro area. All 13 CVAP categories available. Export the county-level precinct table directly for use in GIS or election analysis software.
Open County ExplorerDownload the full VTD-level CSV for any state — all 13 CVAP categories plus VAP categories, one row per VTD. Includes state FIPS, county FIPS, VTD code, and geographic centroid coordinates. Formatted for direct merge with election returns or shapefiles. Includes a complete data dictionary and methodology citation for court filings.
Download by StateWho Uses This Platform
Gingles Prong One requires demonstrating that the minority group is sufficiently large and geographically compact to form a majority in a single-member district. Prongs II and III together provide the empirical framework for racially polarized voting analysis — whether the minority votes cohesively and whether that cohesive vote is typically defeated by bloc voting of the majority. This platform provides the demographic foundation — precinct-level CVAP and VAP by race — that anchors all three Gingles prongs in reproducible, court-admissible data.
Draft and evaluate proposed district configurations using VTD-level building blocks. Compare Black CVAP share, Hispanic CVAP share, and Any-Part Black CVAP across alternative maps before the remedial hearing. Any-Part Black CVAP — the sum of Black Alone, Black-White, and Black-AIAN CVAP — is available as a named metric because it is the measure courts have accepted for Gingles Prong One analysis.
Thirteen CVAP categories and nine VAP categories at the precinct level, for two decennial cycles, covering all 50 states. Cite the methodology documentation directly in published work — all inputs are public Census Bureau files and the interpolation method is fully described and reproducible. Download full datasets in CSV format with complete codebooks.
The block-level population-weighted disaggregation methodology underlying this platform was accepted in Allen v. Milligan, 599 U.S. ___ (2023), in which the Court affirmed that Section 2 of the Voting Rights Act requires Alabama to draw an additional majority-Black congressional district.
On the Limitations of Block-Group Interpolation: CVAP estimates at the VTD level are derived values, not direct Census Bureau tabulations. The ACS block-group CVAP figures carry margins of error that are not propagated through the interpolation. For precincts with very small populations, estimates should be treated as approximate. The methodology documentation provides guidance on interpreting results in litigation contexts and on communicating the interpolated nature of VTD-level CVAP estimates to the court.