Block-based US sovereignty history — a static D3 visualization that paints the continental US as a pixel grid colored by the historical sequence of sovereign powers that ruled each location.
Hover any cell for the full sequence (e.g. France → Spain → France → USA for the Louisiana Purchase, or Spain → Mexico → Bear Flag Republic → USA for California). Scroll/pinch to zoom. Drag to pan.
15 sovereignty sequences, including:
- Original colonies + Northwest Territory — Britain → USA
- New Netherland — Netherlands → Britain → USA
- New Sweden (Delaware) — Sweden → Netherlands → Britain → USA
- Florida — Spain → Britain → Spain → USA
- Louisiana Purchase — France → Spain → France → USA
- Vermont Republic — independent 1777–1791
- Republic of Texas — Spain → Mexico → Republic of Texas → USA
- Bear Flag Republic (CA) — June 14 – July 9, 1846
- State of Deseret (UT) — Mormon proto-state, 1849–1851
- Republic of West Florida — 74-day republic in 1810 (LA Florida Parishes, AL/MS coast)
- Oregon Country — Spain+Russia → Britain+USA → USA, with sub-state overrides for the Continental Divide in MT/WY/CO
- Nueces Strip — disputed between the Republic of Texas and Mexico, 1836–1848
- Oklahoma Panhandle ("No Man's Land") — unorganized 1850–1890
Continental US only. AK / HI / territories are deliberately excluded.
No build, no install — just serve the directory over HTTP and open it.
python3 -m http.server 8080
# open http://localhost:8080file:// won't work — data/us-states.json is fetched, so the page must be served via HTTP.
| Path | What's there |
|---|---|
index.html |
Markup, CDN script tags for D3 + topojson-client, viewport chrome (title, legend, tooltip). |
js/app.js |
Renderer — projection, grid sampling, point-in-polygon lookup, SVG draw, zoom/pan. |
js/territories.js |
Data layer — FIPS map, state-level sequences, sub-state overrides, sequence labels/descriptions/colors. |
data/us-states.json |
TopoJSON of continental US state and nation outlines. |
css/style.css |
Dark-theme styling for the map, legend, tooltip. |
See CLAUDE.md for the architecture, key constants, and how to add a new sovereignty sequence.
MIT — Copyright (c) 2026 Dan Ziegler