Roscommon to Chase Bridge
Small and quick
Narrow, fast water with tight bends. Good boat control needed.
Lower Peninsula River Guide / Lake St. Helen to the Au Sable mainstream
South Branch Au Sable River Kayaking Guide: Launches, Dams & Flows
Wild Rivers. Rugged Trails. Real Adventure.
The South Branch runs from Lake St. Helen past Roscommon and through the Mason Tract, a protected wilderness corridor of pine and cedar with no cottages along its banks. The Chase Bridge to Smith Bridge run is one of the most beautiful and peaceful day paddles in Michigan.
RegionNorthern Lower Peninsula, Au Sable country
CountiesRoscommon, Crawford
WatershedAu Sable River
Great Lake BasinLake Huron
River LengthLake St. Helen to the mainstream
PaddleableRoscommon to the mainstream
Best SeasonMay to October
MouthAu Sable River, South Branch Township
Before you launch: a quiet trout river
- Anglers: this is famous trout water. Pass anglers quietly and give them room.
- Sweepers and gravel bars: fallen trees and gravel bars can catch a boat. Watch the bends.
- Not a party river: the Mason Tract is managed as a quiet, natural area. Keep it that way.
- Cold water: the spring-fed South Branch stays cold. Dress for a swim.
River History
Like the rest of the Au Sable, the South Branch was logged hard in the late 1800s, and its name comes from the French for "river of sand." Afterward, the clear, cold river became famous for trout and drew wealthy anglers to private clubs and lodges along its banks.
George W. Mason, an auto executive and devoted trout fisherman, left his South Branch land to the state when he died in 1954, asking that it be kept wild. That gift became the Mason Tract, a corridor of protected state land along the river. In 1960 the Mason family built the small Mason Chapel on a hill above the river, which paddlers still visit today.
River Map
River Overview
The South Branch rises from Lake St. Helen in Roscommon County, flows northwest through the village of Roscommon, then turns northeast through the Mason Tract to join the Au Sable mainstream in South Branch Township, Crawford County. It’s a cold, clear, sandy river fed by groundwater, with steady current and many bends.
Lake St. Helen
The river’s source in Roscommon County.
Roscommon
The river passes through the village. Liveries and campgrounds nearby.
Chase Bridge
Start of the classic Mason Tract day trip.
Mason Tract
Protected wild river with no development. Mason Chapel sits on a hill on the east bank.
Smith Bridge (M-72)
End of the classic run, about 10.2 miles below Chase Bridge.
Au Sable mainstream
The South Branch joins the main river a few miles below, near Canoe Harbor.
USGS Flow & Water Conditions
The USGS gage near Luzerne is on the lower South Branch and is the one to check. Spring-fed rivers like this one hold steady flows, so big changes usually mean heavy rain.
How to read it
Compare today’s flow with the typical flow for the date shown on the USGS graph. Well above normal means faster current, debris coming downstream and fewer safe eddies. Well below normal means more dragging and more liftovers.
After heavy rain, check again the morning you launch. Small rivers rise and fall quickly.
Paddling Character
Mason Tract
Wild and peaceful
Mild current, fairly deep water and a sandy bottom through pine and cedar forest with no development.
Below Smith Bridge
Bigger water
Wider, slower water as the South Branch nears the mainstream.
Michigan Water Trails
The South Branch is not a designated Michigan Water Trail, but the Mason Tract protects its banks as public land and keeps it wild.
Check the official list for updates, since new trails are added over time.
Michigan Water TrailsDams & Portages
South Branch
No dams on the paddling stretch
There are no dams between Roscommon and the mainstream. The nearest dams are on the mainstream far downstream, starting at Mio.
Launches
Listed upstream to downstream. Confirm parking, fees and current conditions before you go.
Roscommon
Roscommon area liveries
Several liveries in Roscommon run trips and shuttles on the South Branch.
MapMason Tract
Chase Bridge
Put-in for the classic 10.2-mile Mason Tract run.
MapM-72
Smith Bridge
Take-out for the Mason Tract run, on M-72.
MapConfluence
Canoe Harbor
State forest campground near where the South Branch meets the mainstream.
MapCamping
Confluence
Canoe Harbor State Forest Campground
Rustic DNR campground near the mouth of the South Branch, a good base for the South Branch and the mainstream.
Roscommon
Roscommon campgrounds
Private and state campgrounds in the Roscommon area, close to the upper river.
Mason Tract
Respect the tract
Check DNR rules before camping on Mason Tract land. Stay on designated sites.
Wildlife & Fishing
Wildlife
Deer, otter, mink, beaver, eagles and kingfishers are common. The pine and cedar forest of the Mason Tract shelters songbirds and the occasional black bear.
Fishing
The South Branch is one of Michigan’s best-known trout streams, with brown and brook trout. Special regulations apply on parts of the river. Check the current fishing guide.
Safety
Safety essentials
- Wear your PFD the whole time.
- Watch for sweepers and gravel bars on the bends.
- Pass anglers quietly and give them space.
- Dress for cold water, even in summer.
Rules, passes and private land
- The Mason Tract has its own rules. Keep groups quiet and leave no trace.
- A Michigan Recreation Passport is needed at state parks and many state-run launches.
- Much of the riverbank is private. Stop only on public land or where you have permission.
- Leave No Trace: pack out all trash.
What to pack
- Spare paddle, bilge pump, throw bag and whistle
- Dry bag with warm layers
- Map or GPS track with your take-out marked
- Warm layers for cold mornings
Best Time & Access
Spring
High, cold water. Fewer people.
Summer
The best season. Busy with anglers at dawn and dusk.
Fall
Great color in the Mason Tract.
Winter
Open water but very cold. Experts only.
From Grand Rapids, Roscommon is about two and a half hours north. Take US-131 north to US-10 east and US-127 north, then I-75 to Roscommon.
Trip Planning
Classic day trip
Chase Bridge to Smith Bridge is 10.2 miles, about 3.5 to 5 hours.
Overnight trip
Combine the South Branch with the mainstream for a multi-day trip, camping at Canoe Harbor.
Shuttles
Roscommon liveries run shuttles, or leave a car at Smith Bridge.
Check before you go
Look at the Luzerne gage and the weather.
River Difficulty
We use the American Whitewater difficulty scale. The South Branch is easy moving water with no real rapids, so it’s rated Class I. Sweepers and quick bends upstream take good boat control.
Chase Bridge to Smith Bridge
Mild current through the Mason Tract. Good for most paddlers.
Roscommon to Chase Bridge
Quicker, tighter water with more bends.
Quick Reference
| Source | Lake St. Helen, Roscommon County |
|---|---|
| Mouth | Au Sable River, South Branch Township |
| Protected land | Mason Tract |
| Classic run | Chase Bridge to Smith Bridge, 10.2 miles |
| Dams | None on the paddling stretch |
| Main town | Roscommon |
| Key gage | USGS 04135700, near Luzerne |
| Michigan Water Trail | Not designated |
| Best season | May to October |
| Difficulty | Class I |