Main Branch Au Sable River Overview

by Tom Quail, Au Sable River Guide Service

The Au Sable River, located in the northern Lower Peninsula, is arguably the finest trout fishery east of the Mississippi River and North America. There are those who argue that the Catskills, the limestone creeks of Pennsylvania, and Upper Delaware are as good or better. But, I believe the Au Sable can make a very strong case as the granddaddy of them all.

Several factors make the Au Sable so great. It’s approximately 138 miles long, starting just south of the town of Gaylord, and runs south and east, emptying into Lake Huron. It’s primarily a spring feed resource with cold temperatures, a decent gradient, good structure, and good shading, helping to keep the temperatures low enough to support a healthy trout population year-round.

There are four branches to the river – the Main Branch, East Branch, South Branch, and North Branch – all with numerous tributaries, all with brook, brown, and rainbow trout.

The productive trout water on the Main Branch starts around the town of Frederic, moving south to Grayling. At Grayling, the East Branch joins the Main Branch. About four miles, as the crow flies, east of Grayling, the Holy Water begins at Burton’s Landing.

The Holy Water is the nine-mile stretch of river between Burton’s Landing and Wakeley Bridge that is regulated as flies only and catch-and-release only. It is best wade-fished with a plethora of access points. Boats are allowed, particularly Au Sable riverboats, canoes, and kayaks. It’s advised NOT to float a drift boat down the Holy Water; while it is legal, it is frowned upon by local custom. By reputation, it’s among the best stretches of dry fly fishing water in Michigan and, perhaps, the eastern United States.

East of Wakeley Bridge, running downstream to McMasters Bridge, is a very productive trout fishery. This stretch is artificial flies/lures only, with no restriction on the type of fishing. Per regulations, “catch and keep” fishing is allowed. Along this stretch, the South Branch joins the Main Branch. While the fish count per mile is slightly less than the Holy Water, the catch size is typically larger. This beautiful stretch of river, including the South Branch, has numerous wading opportunities and very manageable floating conditions.

Downstream from McMasters Bridge to Mio Pond is very productive water with slightly lower fish counts per mile but larger fish. The North Branch joins the Main Branch in this stretch. This part of the river, while it can be waded, is best fished with some type of watercraft.

Below Mio Pond, the furthest upstream dam is located, Mio Dam, in the city of Mio. Here the river turns into a tailwater fishery. While the tailwater warms a bit, it stays cold enough to support a good trout fishery year-round, except for a few days during the hot summer months. The stretch between Mio Dam and the 4001 Bridge is good brown trout water. The browns along this stretch can be trophy size, 20+ inches.

From Mio Dam down to the town of Oscoda, where the Au Sable empties into Lake Huron, there are a series of hydroelectric dams, with the last being Foote Dam. The Foote Dam tailwater is a special fishery because it supports trout and salmon species not found in the stretches upstream. This area needs to be floated in a watercraft to be fished productively and safely. There are healthy populations of resident brown trout, anadromous brown trout that come from Lake Huron to spawn, steelhead, and Atlantic salmon, a relatively new species introduced within the last decade.

The Atlantics were cultivated at Lake Superior State University in Sault Ste. Marie and released into the Au Sable below Foote Dam to mitigate the collapse of the Coho and Chinook salmon in Lake Huron. It is an overwhelming success!

Trout are not the only species found in the Au Sable, but it is arguably the most noted. Because of the length of this river, there are many more opportunities than have been mentioned here. There are numerous canoe and kayak liveries, many beautiful overlooks, and stunning stretches of the river.

The Au Sable Main Branch is also home to the Au Sable River Marathon in late July.