| Aavoja | |
| Subdivision Type1: | Country |
| Subdivision Name1: | Estonia |
| Length: | 22.1km (13.7miles) |
| Source1 Elevation: | 67.5m (221.5feet) |
| Discharge1 Avg: | 1m3/s |
| Basin Size: | 69.1km2 |
| Mouth: | Jägala River near Kehra |
| Mouth Coordinates: | 59.3375°N 25.3467°W |
| Mouth Elevation: | 44.5m (146feet) |
| Source1 Coordinates: | 59.3561°N 25.6353°W |
| Source1: | near Koitjärve Bog in Pillapalu |
| Discharge1 Location: | before Aavoja Reservoir |
| Tributaries Right: | Aruoja, Raudoja-Aavoja Canal |
| Tributaries Left: | Verioja |
| Name Other: | Kehra oja, Pillapalu peakraav |
| Progression: | Jägala River → Gulf of Finland |
| Subdivision Type2: | County |
| Subdivision Name2: | Harju |
| Subdivision Type3: | Parish |
| Subdivision Name3: | Anija |
The Aavoja is a 22.1km (13.7miles) long river in Anija Parish, Harju County, Estonia that flows into the Jägala River near Kehra.
The current source is located in the village of Pillapalu, just south of Koitjärve Bog. The upstream part of the river was dug in the 1930s to drain Aguparra Bog.[1]
Väike-Aavoja and Aavoja reservoirs are located on the river. The river is part of the Tallinn water supply system. The basin area of the river is 69.1km2.[2]