This is a list of secondary highways in Thunder Bay District, most of which serve as logging roads or provide access to the isolated and sparsely populated areas in the Thunder Bay District of northern Ontario.

[1] The Gull Bay First Nation occupies one of the few permanent settlements on Highway 527, Gull Bay Reserve, situated on the western shore of Lake Nipigon about 70 kilometres south of Armstrong.

Except within the communities of Armstrong and Gull Bay, there are no services or development along this road.

It is served to connect between Highway 11 near Beardmore to Poplar Lodge near Lake Nipigon.

It travels northward, parallel to the Nipigon River, through the community of Cameron Falls to the Pine Portage Hydroelectric Power Plant.

It begins at pass lake truck stop at Highway 11/Highway 17, and ends at Silver Islet, where it makes a 6 km (3.7 mi) loop around to connect with itself.

Later about the 1870s Sleeping Giant Provincial Park was incorporated and Highway 587 was in the planning stages.

It travels west for approximately 12 kilometres then turns due south to terminate at Highway 588 in Nolalu.

It travels west then north and terminates at the corners of Gilbride and Island Lake Roads, 8 kilometres (5.0 mi) northwest of Lappe.

Highway 593 is a 52 kilometre road in the Thunder Bay District of Northwestern Ontario, starting at Highway 61, three kilometres north of the Pigeon River border crossing at the Canada–US border.

It travels west then north and terminates at Highway 588 between Suomi and Nolalu.

[7] It remained unchanged from then until 2015, when construction began on four laning Highway 11/17 between Red Rock Road 9 and Stillwater Creek.

The route was extended approximately 350 m (1,150 ft) west in June 2019 to the newly opened four lane highway.

Its total length is approximately 19.6 kilometres (12.2 mi) and runs roughly on a northwest–southeast orientation.

A proposed all-season access road would connect Marten Falls First Nation to Highway 643.