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World-Class Fly Fishing with a Family’s attention to detail

Booking Now for 2026

Welcome to

On DeMark Lodge

An All-Inclusive Fly Fishing Retreat on Montana’s Missouri River

Nestled between Helena and Great Falls, On DeMark Lodge is an intimate, family-run fly fishing lodge on the Missouri River offering world-class trout fishing, warm hospitality, and a true taste of Montana life.

Just minutes from the water, our guests enjoy easy access to some of the best brown and rainbow trout fishing in the country— all from the comfort of an all-inclusive lodge.

A Stay That Feels Like Home

Owned and operated by the DeMarks, attention to detail is everything. Every feature is designed with care, from home-cooked meals to cozy gathering spaces and a welcoming atmosphere that reflects our love for what we do. Hosting up to six guests, our lodge features three comfortable rooms — each with two queen beds and a private en suite bathroom.

World-Class Fly Fishing on the Missouri River

The Missouri River offers 4,000–7,000 trout per mile in a stunning 40-mile stretch from Holter Dam to Cascade — one of the richest fisheries in the United States.

With 11 different boat launches nearby, our expert guides put you on the big, hard-fighting trout the Mo’ is famous for.

Evenings Worth Remembering

After a day on the river, relax on the deck overlooking the “Mighty Mo” with a drink in hand as the sun sets over the valley. Share stories, spot wildlife, and take in the breathtaking scenery that makes this part of Montana so special.

Unforgettable fishing. Exceptional hospitality.


At On DeMark Lodge, every trip feels like coming home.

"There is no greater fan of fly fishing than the worm"

- Patrick F. McManus