[3] The highway travels northeast from Port Hastings along the base of a group of mountains known as "The Big Ridge" to Whycocomagh.

It then follows the north shore of Bras d'Or Lake, bypassing Baddeck on a short Super two controlled access segment.

Still running in a general northeast direction, at St. Anns the highway begins ascending the west slope of Kelly's Mountain on the Cape Dauphin Peninsula.

Highway 105 descends the east slope of Kelly's Mountain using a series of sharp turns including a 180° hairpin turn at New Harris Forks before crossing the Great Bras d'Or Channel of Bras d'Or Lake on the Seal Island Bridge.

Highway 105 regains controlled access for the final 3 km (1.9 mi) to its eastern terminus at the Marine Atlantic ferry terminal in North Sydney where travellers can continue to Newfoundland.