In the 1920s and 1930s Albert Everett Wieslander and several others explored much of California's wilderness sampling vegetation, taking photographs, collecting specimens, and drawing detailed maps of what they found. The collection is now known as the Wieslander Vegetation Type Mapping (VTM) collection, and the entire survey encompassed nearly seventy million acres of the state, covering most of the wild areas exclusive of the deserts and the larger agricultural areas. These data represent a valuable resource for comparative and conservation ecology. We are digitizing the entire project, and making it available to researchers and the public. The current “VTM Digitization” Project, as it is known, is described in this article, and is a collaborative effort by teams at University of California Berkeley and University of California Davis, funded by the U.S. Forest Service and U.S. Department of Agriculture's Cooperative State Research, Education and Extension Service. The VTM Digitization Project aims to digitize the entire VTM collection for use in ecological and geospatial analyses, and to facilitate access and distribution of the data by researchers and interested parties. This article describes our efforts at making the VTM plot data, maps and photographs digital, spatially referenced, readily available, and web-accessible via an Internet-based Geographic Information System (webGIS) application. In addition, we discuss potential uses for the data and caveats associated with its use, particularly spatial accuracy.