Interactive Cartography of Spanish and Mexican California
Maps of the expeditions, engagements, and imperial contests of California between 1769 and 1848, reconstructed point-by-point from the archival record — above all the Archives of California (BANC MSS C–A), the Savage transcript copies that are the sole surviving record of the province's government archive after 1906. Every pin carries its source; uncertain locations are drawn so you can see the uncertainty.
Native California
Approximate homelands of the Native nations of Alta California at contact, labeled without invented boundary lines and grouped by language family. Companion to the Native Peoples Index.
Military Engagements, 1769–1848
Every documented engagement from the project's military register — treating Indigenous combatants as military actors, with campaign layers, a timeline, and register-keyed citations.
The Presidial System, 1769–1846
The garrisons and artillery of the four presidios from the muster rolls and ordnance inventories, fort by fort and year by year, with Fort Ross as the benchmark one Russian outpost set for the whole coast.
The Bodega–Ross Corridor, 1775–1841
Sixty-six years on one stretch of coast: the 1775 survey, the failed 1793 occupation, the Russians at Ross, the Spanish probes that watched them, and the Coast Miwok who dealt with everyone. Companion to a research article in progress.
Population of the Californias, 1777–1847
Every count in the archive, settlement by settlement, in the documents' own categories. The headline: in 1790 the entire Spanish population of Alta California was 910 people.
Missions & Establishments, 1769–1846
Every fixed establishment of colonial California: the mission chain and its sub-stations, the Russian fort, port, and farms on the Sonoma coast, and New Helvetia on the Sacramento. Slide the timeline to watch the chain grow.
The Bay Area Imperial Frontier, 1775–1841
San Francisco Bay as a contested borderland: Spanish defense and decay, Russian hunting and settlement, British and American probing — and the Native peoples who navigated all of them.
Gabriel Moraga's Expeditions, 1806–1817
A decade of interior and northern reconnaissance on one map — the 1806–07 valley probes, the 1810 Suisun and Bodega operations, and the Ross missions of 1812–13.
The 1806 Interior Expeditions
Zalvidea and Moraga's 1806 probes into the Central Valley, camp by camp from the Muñoz and Zalvidea diaries, with the Native villages they passed through as Cook identified them.
About & Method
These maps accompany a research project on Spanish- and Mexican-era California. They exist to make the geography of the archival record legible: where expeditions actually went, which Indigenous communities they passed through, and how competing empires pressed on the province.
Method. Routes are reconstructed stop-by-stop from expedition diaries and S. F. Cook's route studies; engagements are plotted from a maintained register compiled out of the C–A transcripts, Bancroft, and printed primary collections, and each map pin is verified against that register before plotting. Coordinates are best-available reconstructions, not surveyed points: solid markers sit at known places, translucent dashed markers are approximate within their district, and hollow markers are conjectural. Dashed route lines mean the party passed roughly this way. A small number of register entries (documents without a plottable location) appear only in the register, not on the map.
Native California. Most of the violence documented here was carried out against, and often alongside, Native Californians — as combatants, auxiliaries, intelligence sources, and polities defending territory. The maps use the sources' own terms inside quotation marks and name Native nations, villages, and leaders wherever the documents allow. "Punitive expedition" and similar phrases are the sources' framing, not an endorsement.
AI assistance. This site is built and maintained with substantial AI assistance (Anthropic's Claude), under the author's direction: the register compilation, verification passes, data files, and site code are AI-drafted and human-reviewed. Errors are mine; corrections are welcome and logged.
Companion project. The same research maintains Archives of California: A Documentary Calendar of the Savage Transcripts (DOI 10.5281/zenodo.21327098) — map pins with a catalog record deep-link straight to it, and from there to the manuscript leaf.
Sources
Primary. Archives of California (BANC MSS C–A), The Bancroft Library, University of California, Berkeley — the Thomas Savage transcript copies · Diary of Fr. Pedro Muñoz (Moraga expedition, 1806) · Diary of Fr. José María de Zalvidea (1806).
Secondary. Sherburne F. Cook, Colonial Expeditions to the Interior of California: Central Valley, 1800–1820 (Berkeley, 1960) · Hubert Howe Bancroft, History of California, 7 vols. (San Francisco, 1884–1890) · John P. Langelier & Daniel B. Rosen, El Presidio de San Francisco (1992) · A. L. Kroeber, Handbook of the Indians of California (1925) · E. W. Gifford & W. E. Schenck, Archaeology of the Southern San Joaquin Valley (1926).
Data & Reuse
Each map is driven by an open JSON dataset in
the repository's
data/ directory (schema documented there). Content is licensed
CC-BY-4.0, code MIT. To cite a
specific feature, use its permalink (the 🔗 link in any popup); to cite a map, use the
"Cite this map" button on the map page. No build step, no tracking.