Rayakoski (Russian: Раякоски; Finnish: Jäniskoski/Rajakoski, Norwegian: Grensefoss lit.

border rapids) is a rural locality (an inhabited locality) in Pechengsky District of Murmansk Oblast, Russia,[1] located adjacent to the tripoint between Finland, Norway, and Russia.

Population: 238 (2010 Census).

[2] Rayakoski is located around the Rayakoski Hydroelectric Power Plant, built in 1956.

In 1947, Finland sold the 169 square kilometer (65 sq mi) Jäniskoski area with its hydroelectric plant, in exchange for Soviet-confiscated German investments in Finland.