Interactive maps, election results, census data and records for Ireland, north and south.

Live site: civgraph.net Support: ko-fi.com/scottmoore0

What Civgraph does

Civgraph is a free, open site for exploring the administrative geography and political history of the island of Ireland. You can look up any townland, ward, constituency, or census area; see how boundaries have changed over time; and browse election results and demographic data.

What's inside

Hundreds of map layers covering every major administrative geography on the island of Ireland, from the 19th century to the present day.

• Maps and Boundaries - Local government districts, wards, DEAs, parliamentary constituencies, Assembly areas, townlands, civil parishes, baronies, counties, and more. Browse by era with the time slider.
• Elections and Results - Assembly, Westminster, local government, European Parliament, and referendum results. Full STV count animations, candidate and party entity pages, and constituency-level visualisations.
• Census and Demographics - Small Areas, Output Areas, Super Output Areas, Data Zones, and settlement boundaries from NISRA and the CSO.
• Physical Geography - Rivers, watersheds, seas, regional divides, and land classifications.
• Built Environment and Communities - Peacelines, railways, travel-to-work areas, settlements, and place names.
• Spatial Search - Find any boundary feature by name across all map layers.
• Time Slider - Explore how boundaries have changed decade by decade.
• Conditional Styling - Dynamic map styling based on data attributes.

Coverage

Type	Examples
Local government	Districts, wards, DEAs, local authorities
Parliamentary	Westminster constituencies, Dail constituencies, European Parliament regions
Assembly	Northern Ireland Assembly constituencies and regions
Communities	Townlands, settlements, place names
Historical	Civil parishes, baronies, counties, historic council boundaries
Census	Small Areas, Output Areas, Super Output Areas, Data Zones
Physical	Rivers, watersheds, seas, regional divides
Built environment	Peacelines, railways, travel-to-work areas

How it's built

Layer	Technology
Maps	Leaflet with FlatGeobuf for streaming vector data
Build	esbuild with code splitting and performance budgets
Search	Fuse.js for map search, spatial index for feature search
Geospatial	Turf.js for area/length calculations
Testing	Playwright
Hosting	Cloudflare Pages + R2

Run the site on your computer

# Install dependencies
npm install

# Build JS bundle + minified CSS
npm run build

# Start local server
python -m http.server 5050

# Open http://localhost:5050

Project structure

js/
  app.js                  # Entry point, wires all modules
  map-controller.js       # Leaflet map, layers, LOD selection
  ui-controller.js        # Split-pane layout, catalogue, search
  feature-loader.js       # Viewport-aware spatial index + per-feature loading
  election-controller.js  # Election results, STV animation, entity pages
  data-service.js         # Map/book metadata queries
  time-slider-controller.js
  conditional-styling.js
  election-utils.js       # Shared formatters (dates, body names, links)

data/
  database/
    maps.json             # Map layer registry
    spatial-index.json    # Feature search index
    spatial-index/        # Per-map chunks for on-demand loading
  maps/                   # FlatGeobuf files (R2-hosted, multi-LOD)

build/                    # esbuild output (code-split bundles + minified CSS)
scripts/                  # Build and data processing scripts
functions/                # Cloudflare Pages Functions

Build

node scripts/bundle.mjs

Produces:

• build/app.bundle.js - Main bundle (~286 KB)
• build/election-controller-*.js - Lazy-loaded election module (~179 KB)
• build/chunk-*.js - Shared code (~77 KB)
• build/main.css - Minified CSS (~203 KB)

The build enforces performance budgets and fails if the main bundle exceeds 313 KB or CSS exceeds 225 KB.

Spatial index

The feature search index can be rebuilt from FlatGeobuf sources:

node scripts/build-feature-index.js

This generates:

• data/database/spatial-index.json - Monolithic index (fallback)
• data/database/spatial-index/*.json - Per-map chunks (loaded on demand)
• data/database/spatial-index/_names.json - Lightweight search index (~3 MB)
• data/database/spatial-index/_manifest.json - Chunk manifest

Tests

npx playwright test

Author

Created by Scott Moore. The project includes works from various individual contributors and organisations, as attributed on the website.