The Regional Collection is comprised of resources that have a local and regional focus and contain the following geographic areas:  the City of Thunder Bay, neighboring communities, and the greater areas of Northwestern Ontario and Northeastern Ontario.

Northwestern Ontario contains the City of Thunder Bay as well as the Districts of Thunder Bay, Rainy River and Kenora, and this segment of the collection is extremely comprehensive in nature.  Northeastern Ontario is also represented, although at a less comprehensive level and pertains to the Districts of Cochrane, Algoma, Sudbury, Timiskaming, Nipissing, Manitoulin and Parry Sound.

The Regional Collection is an extremely valuable resource for researchers as it pulls together unique and irreplaceable materials that pertain to this geographic area. The subject coverage is extensive and includes:  local history, municipal government, Lake Superior, economic development, forestry and natural resource management, ecology, geological surveys, mining and exploration, parks and tourism, industrial planning, transportation, health care and public health issues, and social service delivery.  A special feature of the collection are the many rare publications from the early days of Port Arthur and Fort William.

In addition the collection contains hundreds of original documents from two separate government studies: Class Environmental Assessment for Timber Management on Crown Lands (Class EA) and the Royal Commission on the Northern Environment.

A significant focus of the Regional Collection are resources pertaining to Indigenous Peoples and is quite comprehensive in nature. Researchers will find a vast selection of materials that relate to all aspects of history, culture, language, treaties, and other special topics.