Grayling, MI • Brown Trout • Rainbow Trout • Brook Trout

Au Sable Holy Waters

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Current Conditions

Flows are around 954 cfs and holding steady, above normal for late August (Nearest active mainstem gauge — at Mio, downstream of the Holy Water). Water was 63°F at the gauge. Gates Au Sable Lodge reported terrestrials, Isonychia and Tricos on Aug 28. Streamers and nymphing for rainbow trout and carp in recent reports.

Conditions as of Aug 30, 2026 Reported by Gates Au Sable Lodge

Au Sable Holy Waters Fishing Report

Evening Rises: ExcellentStreamer: GoodHex Pending

Evening rises on sulphur and PMD hatches have been exceptional. Hex season approaches — watch water temperatures closely. Nymphing the braids near Stephan Bridge has been reliable through the day. Fish run 12–18 inches with occasional 20+ inch browns.

Live Flow Conditions

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USGS Site: 04136500 • Au Sable River at Mio • View full data ↗

Nearest active mainstem gauge — at Mio, downstream of the Holy Water

Hatch Calendar

SpeciesJanFebMarAprMayJunJulAugSepOctNovDec

HendricksonEphemerella subvaria

Sulphur / PMDEphemerella dorothea

Brown DrakeEphemera simulans

HexHexagenia limbata

TricoTricorythodes spp.

Mahogany DunParaleptophlebia spp.

Gear Recommendations

The Holy Water is one of America's premier dry fly rivers. Technical, clear water demands precise presentation and fine tippets.

Gear	fly Dry FlyRecommended	rod Nymphing	rod Euro Nymph	fish Streamer
Rod	9ft 4-weight or 5-weight	9ft 5-weight	10.5–11ft 2-weight or 3-weight	9ft 6-weight or 7-weight
Line	Double-taper floating (DT4F or DT5F) — less splash on presentation than weight-forward	Weight-forward floating with a strike indicator setup	Level 20lb Maxima or dedicated euro nymph line	WF floating or intermediate sink tip
Leader	12–15ft tapered leader	9ft tapered to 4X, add 18–24in tippet	Long mono rig (20ft+) with sighter section	6–9ft tapered to 1X–2X
Tippet	5X–7X fluorocarbon	5X–6X fluorocarbon	6X–7X fluorocarbon	1X–2X fluorocarbon or 15–20lb mono
Waders	Chest waders or hip waders in summer	Chest waders	Chest waders	Chest waders
Boots	Felt-soled wading boots (rubber with studs acceptable)	Felt-soled wading boots	Felt-soled wading boots	Felt-soled wading boots

fly Dry Fly Tips

The Au Sable's flat pools and educated trout demand the finest tippets. Drop to 7X in low clear conditions. The Hex hatch demands a size 4–6 fly so step up to 3X–4X leader for those nights.

Dry fly floatant (Loon Aquel or Frogs Fanny)Amadou patch for drying fliesLong-handled netPolarized sunglasses — essential for spotting risers

rod Nymphing Tips

High-stick nymphing in the braided sections between Stephan and Wakeley bridges. Small bead-head nymphs in size 14–18 match the Au Sable's invertebrate profile.

Thingamabobber indicators (small)Split shot assortment (BB and 3/0)Forceps and nippers

rod Euro Nymph Tips

Czech and French nymphing techniques work well in the Au Sable's riffles and pocket water. The long rod keeps line off the water in the technical dry fly sections.

Putty weight (Loon Biostrike)Small bead-head nymphs size 14–20Colored sighter material

fish Streamer Tips

Night streamer fishing during the Hex hatch produces the largest browns of the season. Mouse patterns on a floating line after midnight are a Holy Water tradition.

Large articulated streamers (sizes 2–6)Headlamp for night streamer sessions during HexWaterproof fly box

Find Your Guide

Gates Au Sable Lodge Guide Service

Orvis Endorsed

📍 Grayling, MIFloat (drift boat) and wade

Gates Lodge has guided the Holy Waters for decades. Their team of working guides includes experts on every section of the Au Sable system.

Specialties

Drift boat float tripsHoly Water wade tripsHex hatch nightsStreamer fishing

Au Sable River Guide Service — Capt. Tom Quail

Independent

📍 Grayling, MIFloat and instruction

Captain Tom Quail, USCG-licensed, specializes in introducing new anglers — especially youth and women — to fly fishing on the Au Sable.

Specialties

Beginners and youthWomen anglersInstruction and casting lessonsHex hatch float trips

Streamside Guide Service

Independent

📍 Grayling, MIWade and float — trophy focused

A true Au Sable specialist focused on trophy brown trout using advanced techniques including mousing and streamer fishing after dark.

Specialties

Trophy brown troutNighttime dry fly and mousingAtlantic salmonCustom rod building

Guide listings are researched and updated periodically. Contact guides directly to verify current availability and pricing.

Local Fly Shops

Gates Au Sable Lodge Fly Shop

Iconic full-service shop on the Holy Water in Grayling — guides, gear, and decades of local knowledge on the river.

Visit website ↗

Old Au Sable Fly Shop

One of the oldest fly shops in America, on the banks of the Au Sable since 1936 — staffed by working guides.

Visit website ↗

Public Access Points

True-traced river course, downstream order ·access / landingbridge

1Burton’s Landingmi 0.02Louie’s Landingmi 0.83Keystone Landingmi 1.34Whirlpool Roadmi 2.05Thendara Roadmi 2.96Stephan Bridgemi 3.67Spite Roadmi 5.68Shaw Parkmi 6.19Wakeley Bridgemi 9.1

🎣 MDNR Regulations 💧 USGS Gauge 📋 Fishing License

River History & Character

The Au Sable River is Michigan's crown jewel of trout fishing, designated a Blue Ribbon trout stream. Fed by cold springs and groundwater seepage through glacial outwash plains, it maintains near-perfect temperatures year-round. The river was central to Michigan's logging era in the 1800s, used to float timber to sawmills downstream. After deforestation threatened the fishery, conservationists — including Aldo Leopold — helped shape the modern forest management practices that protect it today. The Au Sable remains one of the most studied and carefully managed rivers in America.

Did you know

Home to the famous "Holy Water" stretch from Grayling to Mio, considered among the finest dry fly water in North America.

Did you know

The Au Sable Canoe Marathon, held annually since 1947, covers 120 miles through the night from Grayling to Oscoda — the longest non-stop canoe race in the country.