Au Sable River

About

Birthplace of Trout Unlimited — Grayling, Michigan, 1959. Long before liveries and marathons, the Au Sable flowed through the ancestral territory of Indigenous peoples, serving as a primary travel corridor, hunting ground, and gathering place. That older order was reshaped in the treaty era of the 1800s, the framework set by the 1830 Indian Removal Act and the allotment period that ran from the 1840s through the 1890s.

The river's modern character was forged, and scarred, by timber. From the 1830s through the 1920s, the Au Sable watershed was logged to feed the regional timber industry of 1850 to 1910 and the railroad expansion of 1860 to 1910. Local sawmills, logging drives, and downstream lumber operations were the major operators. The end came in stages: the old-growth stands were exhausted by 1910, state forestry conservation began in 1915, and the establishment of state forests in the 1930s closed the book on large-scale logging.

The first hard measurements of the river arrived alongside the loggers. USGS survey work spanned the 1870s through the 1890s, gauging stations followed between the 1880s and the 1910s, and state geological streamflow assessments filled the 1910s through the 1930s — the first comprehensive hydrological studies of the watershed. State water pollution control studies in the 1950s through 1970s and Clean Water Act assessments from 1972 to 2000 later reckoned with more than a century of logging, agricultural, and industrial impacts.

It was the fishing that made the Au Sable famous. In 1959 it became the birthplace of Trout Unlimited, and the coldwater ethic that organization championed still defines the river. The Au Sable Canoe Marathon, run each July since 1947, added a second identity — a 120-mile nonstop test that ties Grayling to the Lake Huron mouth in a single grueling night-and-day push. Recognition followed the reputation: the Au Sable was designated a National Wild & Scenic River in 1984, and it also carries Michigan Natural River status alongside its Trout Unlimited conservation standing.

Today the river is managed as much as it is paddled. Since 2010, the regional DNR and local watershed partnerships have worked to undo a hundred years of damage, with streambank stabilization from 2015 to 2024, native fish restocking from 2017 to 2024, a nutrient reduction strategy implemented between 2018 and 2024, and water-quality gains from 2020 to 2024. Trout Unlimited's 2024 lunker-structure habitat work and a 2023 climate-change assessment produced with Michigan State University continue that effort. For paddlers, the Au Sable divides into three distinct trips: Grayling to Mio, a 50-mile popular family float; Mio to Oscoda, 70 miles of multi-day tripping; and the South Branch, 20 solitary and wild miles. Grayling-based Carlisle Canoe Livery and Penrod's Au Sable handle rentals, shuttles, and put-ins.