New on the Ontario Genealogical Society website, a unified search capability across many of the library catalogues of OGS Branches. Find it under the Libraries tab on the top banner.
Included are holdings of the OGS Provincial Library at the Toronto Reference Library, the British Home Child SIG, and various branches — Essex, Halton-Peel, Huron, Kawartha, Kent, Niagara Peninsula, Ottawa, Oxford, Quinte, Simcoe, Sudbury and Waterloo.
The detail available varies. Ottawa has more comprehensive descriptions of the branch library holdings than the other repositories.
A quick rundown of other library catalogue sites of interest.
and local public and university libraries.