The Kvichak River is a river in southwestern Alaska, located at the conjunction of the Alaska Peninsula, to the Alaska mainland at about With headwaters in Lake Iliamna, it drains the lake into Kvichak Bay, an arm of Bristol Bay. The river is about 97 km (60 mi) long. The communities of Levelock and Igiugig lie on the Kvichak River. The Kvichak is navigable along its entire length, and is used as a short cut by boats getting between Cook Inlet and Bristol Bay via the Lake Iliamna portage.
The Kvichak River is part of the watershed downstream of the proposed Pebble Mine.
Historically, the river was navigated and subsistence fished by local Alaska Natives. The name of the river means from- or up to- great water, a reference to Iliamna Lake, Alaska's largest freshwater lake.