The Chimehuin river begins at Lago Heuchulaufquen.

This place is known as the world famous "Mouth of the Chimehuin" or "Boca of the Chimehuin.” Here is where the 25.5 lbs. Argentina's Brown Trout record with a Yellow Blonde streamer was caught, and with a dry fly (Black Caddis) another Brown of 15.7 lbs. Jose “Bebe” Anchorena owns both records.
It is a typical freestone river with lots of side channels and islands. It runs for approximately 34 miles before merging with the Collón Curá river. It starts off with fast water typical of high gradient rivers, rapidly changing into a medium gradient stream with moderate current and numerous pools, riffles and runs.
The stream beads are composed mostly of large gravel and boulders.
It is a great river with a lot of variety of runs and pools, and you can catch browns and rainbows on dries, wets or nymphs.

• Chimehuin River, this river is one of Argentina’s most recognized rivers, it can be floated in 1 day trips or 2 days with overnight camping. It is a challenging river with lots of willows on the banks, with great riffles and places to stop and wade along the way.