Kasilof River, Brook in Kenai Peninsula, US

Kasilof River is a waterway on the Kenai Peninsula that flows from Tustumena Lake to Cook Inlet. The water moves swiftly and runs cold year-round because glaciers feed it upstream.

Russian settlers named this waterway Reka Kasilova, which later transformed into Kasilof through English adaptation. The name change reflects European expansion into the region during the colonial era.

The river's Dena'ina name is Ggasilatnu; "Kasilof" instead comes from Reka Kasilova, given by early Russian settlers. Salmon fishing remains the river's main use: drift and bank fishing for salmon is popular on the lower Kasilof, and Crooked Creek's confluence is a prime spot.

You can reach the river at three different State Parks locations, including the Kasilof River State Recreation Site with a boat launch for day-use visitors. The current is powerful, so take care when approaching the water or planning water-based activities.

The river was first charted in 1852 by Russian hydrographer Mikhail Tebenkov on the orders of Ilia Voznesensky, so its course appeared on maps before any American survey. Its Dena'ina name, Ggasilatnu, is still recorded alongside the Russian-derived Kasilof.