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	MapLibre GL rendering PMTiles vector tiles; FlatGeobuf is a download format, not a render path
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

Read this before anything else. Several directory names are historical and will mislead you. This section is the canonical layout; CONTRIBUTING.md covers the workflow that goes with it.

Path	What it actually is
app/	the live site — MapLibre GL. Built bundle in app/build/, committed.
src/	shared browser modules, served unbundled. Live, not legacy.
render/src/	shared renderer source; app/ builds from it
render/metadata/	the render catalogue — see "three stores" below
tests/	the Playwright suite
test2/	a compatibility redirect. Not a directory of tests.
apps/	standalone apps (PRONI search). Unrelated to app/.
browse/	the Browse page — hand-written, no build step
pages/	standalone pages (About, Census Explorer)
functions/	Cloudflare Pages Functions
scripts/	build, validation and data pipelines — not deployed
data/database/	the tracked catalogue: maps.json and friends
data/maps/	geometry, served from R2, not from this repository
archive/	superseded code kept for reference. Do not build on it.

Two traps in particular:

• src/ is not the old Leaflet stack. js/ was renamed to src/ when Leaflet was retired, and only the dead parts moved to archive/leaflet/. What is left is live and load-bearing — app/src/app.js imports it on line 3. This README described js/ as the entry point for months after that rename, which is where the "src/ is dead" belief came from; it cost 36,028 lines of live code its linting. See docs/review/TECH-DEBT-AUDIT.md item 4.
• app/ and apps/ are different things, as are render/, test2/ and tests/. Renaming them is planned but invalidates clones, so it is scheduled rather than done: docs/directory-rename-runbook.md.

The catalogue is three stores

The single most confusing thing here, and getting it wrong reliably produces convincing but false "this layer is broken" diagnoses. Joined by a bare string id, with a -vector-test suffix on the render side.

Store	Owns
data/database/maps.json	provenance — licence, attribution, downloads
render/metadata/maps-test.json	rendering — tiles, zoom, styling, labels
c1Cards in src/ui-controller.js	navigation — what a user can click

render/metadata/maps-test-index.json and render/metadata/layer-details-test2/ are generated from maps-test.json: edit the source, then run node scripts/build-test2-metadata-shards.mjs. The client fetches the generated detail shards, so editing only maps.json leaves the site showing the old values.

All three edges are guarded by validators in npm run check.

Which URL comes from where

URL	Source
/	index.html + app/build/ (from render/src/) + src/ + build/
/browse/	browse/
/apps/, /apps/proni-search/	apps/
/pages/about, /pages/census-explorer	pages/
/render/	render/ — staging shell, not the public site

Build

npm run build

That chains seven steps; the two that produce the served bundles are scripts/build-shared-shell-assets.mjs (CSS, critical-CSS inlining, thumbnail manifest) and npm run build:test2 (the MapLibre app). Produces:

• app/build/app.bundle.js — the app bundle, committed to the repository
• app/build/app.bundle.css
• build/main.css — deferred CSS, split from assets/css/main.css
• build/main.critical.css — inlined into index.html by the build

The build enforces performance budgets and fails if CSS exceeds 225 KB.

Each of those is referenced from index.html with a ?v= cache token derived from the file's content hash. Never hand-edit a token — npm run check fails if one does not match, because a stale token means returning visitors keep running the old file. scripts/validate-app-shell-cache-tokens.mjs explains why.

This file told you to run a bundle script at scripts/bundle.mjs until 2026-08-17. There is no such file — it moved to archive/legacy-scripts/ when the Leaflet stack was retired. npm run check now verifies that every repository path these documents cite actually resolves, so that particular lie cannot recur.

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.

Licence

The code is MIT. See LICENSE. You may use, modify and redistribute it, commercially or otherwise, provided the copyright and permission notice travel with it.

The data is not. This repository tracks a large amount of third-party material — census tables, scanned books, boundary metadata — from NISRA, the CSO, OSNI/Land & Property Services, Tailte Éireann, PRONI, the Northern Ireland Assembly, the Houses of the Oireachtas and individual contributors. It arrives under its own terms, predominantly the Open Government Licence and Creative Commons Attribution. Those terms travel with the data and are not superseded by the MIT grant. Per-dataset licence and attribution are recorded in data/database/maps.json (the references and sourceDownloads fields) and data/database/external-sources.json; the entry for a layer is authoritative for that layer.

If you reuse a map layer, credit the originating body — crediting Civgraph alone does not satisfy a source that requires its own attribution.

NOTICE sets this out in full. Licences for the third-party packages compiled into the browser bundle are reproduced in app/build/THIRD-PARTY-NOTICES.txt, generated at build time and verified by npm run check.