Archives are a major resource for primary documents. You can use this guide to aid you in locating archival materials.

Archives Canada - Canadian Archival Information Network
Archives of Ontario
City of Ottawa Archives
Library and Archives Canada - search archival holdings using the Enhanced Archives Search or the older tool ArchiviaNet.
See also the Government of Canada Web Archive and the later version
Ontario's Archival Information Network - a search tool for information on archives and archival records in Ontario
Our Ontario