Historic Shoreline of the San Francisco Bay Area
Seeing the Bay as it once was
This interactive map lets you explore the historic shoreline and wetlands of the entire San Francisco Bay Area as they existed around and before 1900. It is the first time a map like this has been made publicly available, open access, interactive, and free to explore without a paywall.
Unlike other services that simply overlay historic map images on modern geography, this map was built from reconstructed data so you can see where the old and new landscapes truly meet. It offers a clear visual bridge between the past and present Bay, helping viewers understand the scale of change that has taken place along its edges.
How the map was made
This map was handmade by Gabriel Duncan, Paiute, Two-Spirit, and member of the Open Source Geospatial Foundation. It was created using open data and open-source software as part of the Alameda Native History Project GIS Lab.
The shoreline data comes from NOAA’s National Geodetic Survey (NGS), which produces the National Shoreline used to update nautical charts, define territorial limits, and support coastal resource management. NGS gathers shoreline information through aerial and satellite imagery, LiDAR, and other remote-sensing technologies to produce a vector database of the national shoreline.
The base data for this project represents pre-1900 coastal surveys. Historic raster data (converted to vector format), were combined, and stitched together to form a continuous representation of the entire Bay Area. Wetland areas were colored manually based on markings in the original maps to provide a general reference to pre-1900 marshlands.
Because this information was digitized from century-old cartographic records, small distortions and projection differences are expected. The map has been simplified for smooth online performance while preserving as much accuracy as possible.
Acknowledging limitations and purpose
This map is not intended as a precise hydrological dataset. It is a general visual reference showing what the Bay Area looked like around and before 1900. Wetland coloring is approximate and does not depict every historic or seasonal wetland.
The goal is accessibility, education, and engagement, not perfection. It provides a useful overview for environmental educators, researchers, and anyone interested in the Bay’s ecological history.
Indigenous innovation in GIS
This map represents Indigenous leadership in science and technology. It reflects the pioneering spirit of Native people in STEM fields and the role of Indigenous researchers in reclaiming and interpreting the historical landscape of the Bay Area.
By sharing this map openly, the Alameda Native History Project continues its commitment to Indigenous data sovereignty and the responsible use of open data to restore cultural memory and inform the future.
Access and use
This map is hosted on the Alameda Native History Project website and may be used freely for noncommercial educational, environmental, and research purposes.
The underlying dataset is not available to non-Indigenous researchers or organizations. Please contact the Alameda Native History Project directly for inquiries about collaborative or educational use.
Map credits
Title: Historic Shoreline of the San Francisco Bay Area
Creator: Gabriel Duncan
Organization: Alameda Native History Project GIS Lab
Data source: NOAA National Geodetic Survey, Shoreline Data Rescue Project
Software: QGIS
License: Educational and noncommercial use only