Waterfalls and rapids on the map: over 5500 rapids, falls and canyons in Finland, by municipality. Free, no registration or sign-up.
5 587 places in
Most waterfalls & rapids are in Oulu (133), Suomussalmi (118) and Pudasjärvi (116). The full list is below by municipality, and the map can be filtered to your own area.
The remaining places are on the map and in the municipality list.