The lake is about 150 km (93 mi) northwest by road from Victoria, BC's capital on the southern tip of Vancouver Island, and about 60 km (37 mi) southwest by road from the town of Lake Cowichan.

The city of Port Alberni is about 80 km (50 mi) by road to the north.

The southern end of the lake lies in Pacific Rim National Park Reserve, which also contains Nitinat Hill on the lake's northern shore and Nitinat Cone on the southern shore.

Nitinat Lake drains into the Pacific Ocean just north of the Pacific entrance to the Strait of Juan de Fuca via the Nitinat Narrows, a narrow tidal passage about 3 km (1.9 mi) long.

The small First Nations village of Whyac lies on the southern lakeshore beside Nitinat Narrows and just north of the First Nations village of Clo-oose, also on the coast.