A great intermediate section with an easy shuttle that can also be paddled when the lower sections of the river are too high. 
A fun section consisting of multiple grade II+ rapids and two grade III+ rapids in the middle of the trip. Both bigger rapids can be scouted and portaged on river-right. About 500m above the takeout bridge the river splits into two, with the left channel being the best option at the time or writing. This consists of a 100m long, steep, bouldery grade III section that avoids some nasty trees on the right channel. There is also a fun play feature (wave/hole) visible from Harness Cask Road where the river is close to the road about 600m upstream of the takeout. 
Popularity:★★★
Quality:★★★
Reliability:★★★
Grade:III with three grade III+ rapids
Length9km
Elevation and average gradient690m at put-in, 620m at take-out 8m/km average
Paddling time:3 hours
Gauge and level:There is a manual gauge on the downstream side of the Tyringham bridge. The minimum level on this gauge is approximately 0.45m. At the put-in, water should be no lower than about 0.1m below the causeway. As a rough guide the Nymboida@Nymboida electronic gauge would be 2m+.
Put-in:Harness Cask, where Harness Cask Road crosses the river, approximately 6km west of Tryingham Road. 
Take-out:Bridge where Tyringham Road crosses the river, approximately 20km northwest of Dorrigo. 
Shuttle:Easy (2WD). 15 minutes each way via Tyringham Road and Harness Cask Road. It is quite easy to shuttle this section by bicycle.
Maps:Map 2 Nymboida River- Waterfall way to Tyringham
Map 3 Nymboida River- Tyringham to Platypus Flat 
Dundurrabin 1:25,000
Dorrigo 1:25,000