Ammonoosuc
4. Twin Mountain to Pierce bridge
| Difficulty | II-III |
| Length | 3.4 mi |
| Avg Gradient | 41 fpm |
| Gauge | Ammonoosuc River at Bethlehem Junction, Nh |
| Flow Rate as of 1 hour | 2.30 ftbelow recommended |
| Reach Info Last Updated | May 19, 2026 |
River Description
Stone Church Put-In (upper): Access the river close to the route 3 intersection (park behind St. Patrick's Church). The first 2 miles are good for a Class I / II warm up before encountering the continuous class II waters below. Rest Area Put-In (lower): To bypass the extended warm-up section above, find the rest area on state route 302 about two miles west from the intersection of state route 3 in Twin Mountain. Look for a convenient riverside paved pull off across from Beechwood Drive. From the Rest Area Put-In: the river starts with typical boulder strewn class II sections that wend around corners. Look for lots of small play waves and eddies. The first major rapid is Fish Camp Rapid, where the river narrows over class II ledge drops and small holes to dodge. After several quickwater sections alternating with boulder strewn sections, the river gradient increases and comes to a more difficult class II+ section called Boat Breaker just about a half mile upstream of the take out at Pierce Bridge. There is a clear path through river center with some left and right zig-zags to avoid the larger holes. It is easy to boat-scout from resting eddies above each steep portion of this section. The take out is found on the immediate river right after the large concrete abuttments of Pierce Bridge. Most of the river is secluded and out of site of the road with tall northern spruce along the banks. There are occasional camps along the way. Make sure to put on BELOW Lower Falls if you do not want to run a class IV+/V- slide with a very frowny hole at the bottom! (MAP previously indicated a put on above lower falls) ### Technical info Put in elevation........1286'Take out elevation......1167'Total drop..............119'1st mile................46'2nd mile................30'2.9 mile................43' (48' average)Average drop/mile.......41'Distance................2.9 milesRiver width average.....70'River geology...........Small to medium granite bouldersRiver water quality.
River Features
Put In
Take Out
Take out at a big dirt pullout on river left off of Muchmore Rd. 44°16'17.9'N 71°37'55.2'W
Trip Reports
Log in to add a reportRan from the Lower Falls Trailhead to Pierce Bridge. Good class II-III run with the exception of a harder rapid pushing III+ near a pulloff on the south side of 302 (see details on the reach upstream of Twin Mountain). I would call 3.5 a minimum flow for smooth passage. See pics for the take-out parking.
Sharon Lacroix on the mid section of the Ammonoosuc river on a bonus fourth of July summer flow.
Post Irene update.
Carl F and I ran this section on Monday Oct 2nd at 4.07 ft on the gage.
The run is currently clear of strainers and debris.
We had an enjoyable run. Lots of surf and technical eddy hopping.
Enjoy,
Steve Jacques, Bartlett, NH