Data & tiles:
Base map tiles ©
Esri
(World Physical Map) — sources: U.S. National Park Service.
A label-free terrain layer with rivers + lakes + ocean
bathymetry is used here so modern Chinese roads and place
names don't overlay the historical geography.
Historical administrative boundaries (where present) derived from the
China Historical GIS
project (Harvard / Fudan), released under
CC BY-NC-SA 4.0;
individual boundaries are simplified for web display and may not
reflect every historical revision. Place lat/lng coordinates are a
mix of CHGIS centroids and editorial additions. Era covered: Late
Eastern Han through Three Kingdoms (~184–280 AD), with
border snapshots drawn primarily from the Eastern Han (~140 AD)
and Western Jin (~280 AD) CHGIS layers. See
GEO.md
in the project repo for the full sourcing methodology.