Historical census boundary datasets are invaluable resources for mapping and analyzing demographics over space and time. In Canada, finding and using historical census boundary data can be a little difficult. Statistics Canada makes tabular census data available online for the 2011, 2006, 2001, and 1996 Censuses, with some summary profile tables available back to 1991. For boundary files however, fewer censuses are accessible, with only 2011, 2006, and 2001 available online. Today, access to the older collections is typically mediated by Statistics Canada, or academic libraries who have access through the Data Liberation Initiative (DLI) program. Given that the data from these earlier years are not readily available online publically, it prevents researchers from easily accessing and using them. In addition, for some of the older censuses, the digital spatial data are stored in archaic data formats which present challenges for use in modern Geographic Information Systems (GIS).In the fall of 2015, Scholars Portal and the University of Toronto Map and Data Library embarked on a project to bring together the dispersed collection of digital census geography datasets and make them available online so they can be easily accessed by researchers, students, and the general public. This project makes data and documentation available openly through the Ontario Council of University Libraries (OCUL) Scholars GeoPortal platform (http://geo.scholarsportal.info). In making the collection available online openly and all in one place, these datasets will be shared and reused more effectively, thus reducing barriers and duplication for researchers everywhere.This paper outlines the current status of census boundary datasets in Canada and then details our work which includes collecting known datasets from a variety of sources, data conversion, composing a comprehensive set of metadata, and providing online access to the collection. We also compiled an extensive inventory of all known boundaries produced in order to keep track of the collection as well as assess any gaps to help plan future digitization projects. We hope that this work is utilized and shared with others so that more attention is given to this important historical GIS collection.