West of Coombs Junction, Highway 4 travels for before meeting Cameron Lake. Highway 4 hugs the shore of Cameron Lake for , then winds its way through MacMillan Provincial Park, which includes a tourist attraction known as Cathedral Grove. After Cameron Lake, Highway 4 climbs for , following the Cameron River, to the Port Alberni Summit—the highest point on the highway (elevation: ), known by locals as "The Hump", at which it crosses from the Regional District of Nanaimo into the Alberni-Clayoquot Regional District—and then descends for to a spur that travels into the city centre of Port Alberni. Highway 4 enters the city limits of Port Alberni west of the main spur into the city, and later, exits Port Alberni via a bridge over the Somass River.