| Reigolil River | |
| Map: | Mapa No. 31. Provincia de Valdivia-7930038.jpg |
| Map Alt: | Trancura River, east of Villarica Lake in a 1903 map |
| Mouth Location: | Trancura River |
| Subdivision Type1: | Country |
| Subdivision Name1: | Chile |
Reigolil River (Spanish; Castilian: Río Reigolil, pronounced as /es/) is the main tributary to Trancura River in La Araucanía Region, Chile.[1] Reigolil River flows from north to south following the Reigolil-Pirihueico Fault. The river has a catchment area that includes the southern slopes of Sollipulli Volcano in the north and a large portion of land east of Huerquehue National Park.