Armstrong & DePuy’s Spring Creek Fly Fishing
DePuy’s and Armstrong’s spring creeks flow from underground springs at a nearly constant 50–54°F, with clear water, steady flows, and rich insect life all year. These are technical, honest creeks that reward good decisions rather than hero casts.
Stable Water & Technical Fishing
DePuy’s and Armstrong’s Spring Creeks are two segments of the same spring creek system flowing through private ranches in Paradise Valley. Armstrong’s begins on the O’Hair Ranch with roughly 1.3 miles of fishable water; DePuy’s continues downstream for about three more miles before meeting the Yellowstone River. [web:131][web:132][web:135]
Because they are spring‑fed rather than snowmelt‑driven, temperatures stay stable and the water remains clear when many freestones are blown out or frozen. Limited rods, steady hatches, and clear sight‑fishing make these some of the most technical and rewarding fisheries in Montana. [web:126][web:128][web:132][web:135][web:138]
Fishing DePuy’s & Armstrong’s Through the Year
Late Winter & Early Spring (February–April)
Daily midge activity and Blue Winged Olives on overcast days keep fish feeding. Rainbows from the Yellowstone use especially DePuy’s to spawn, and nymphing with eggs, sowbugs, scuds, and small midges can be excellent. This is one of the most forgiving times to learn spring creeks. [web:126][web:129][web:132][web:139]
Late Spring & Early Summer (May–Mid July)
PMDs, caddis, sulphurs, and Baetis create classic hatch days. Mid‑June through early July often brings blanket PMD hatches on both creeks, with size 14–18 duns and emergers driving sustained surface feeding. This is peak dry‑fly season, with the highest rod demand and fees. [web:126][web:128][web:130][web:135][web:137]
Mid‑Summer (Mid July–Mid August)
PMDs taper, but sulphurs, tricos, caddis, and terrestrials keep fish looking up. Weeds are thickest, creating cover and narrow lanes. Mornings and evenings often produce the best mix of spinners and caddis, while midday fishing leans on precise terrestrial and nymph presentations around weed edges. [web:126][web:128][web:134][web:135]
Fall (September–October)
Cooler nights bring consistent Baetis hatches, midges, and the occasional flying ant. Brown trout stage and spawn in pea‑gravel sections, especially on DePuy’s, so we avoid walking redds and do not target spawning fish. Overcast days can offer steady pods of trout feeding in soft currents. [web:126][web:129][web:131][web:132]
Winter (November–January)
When freestones are locked in ice, these creeks stay open with water often in the low‑40s. Midges, scuds, and sowbugs dominate, and DePuy’s in particular is renowned as one of Montana’s best winter fisheries, helped by three wood‑stove huts along the creek. [web:126][web:132][web:135][web:138]
Small Details, Big Results
Weed Edges & Lanes
Trout hold tight to weed beds, subtle drop‑offs, and soft cushions below riffles. Clear water lets you see fish and structure, but it also lets fish see you. Six inches of drift or depth change can turn refusals into eats, so we spend time reading lanes before we ever cast. [web:130][web:132][web:135]
Small Flies & Drifts
Most days revolve around size 18–22 midges, Baetis, PMDs, sulphurs, and small caddis patterns. We use long leaders, 5–7X tippet, and downstream or cross‑stream presentations to cut drag. Sight‑nymphing with scuds, sowbugs, and eggs can be deadly when fish are not rising. [web:126][web:128][web:132][web:136][web:137]
Stealth & Approach
We walk slowly, stay low, and avoid skylines. One well‑planned cast over a feeding fish matters more than several rushed ones. You will learn to watch body language, see refusals, and adjust fly, size, or angle with purpose.
Skills That Travel
Time on these creeks changes how you fish everywhere else. After a day on Armstrong’s or DePuy’s, mending, line control, and fly choice on freestones like the Yellowstone or Madison feel more intuitive. Many guests use winter and shoulder‑season spring creek days as tune‑ups for bigger summer trips. [web:132][web:138]
DePuy’s vs Armstrong’s Spring Creek
DePuy’s is the lower half of the system with more varied structure; Armstrong’s is the upper ranch section with classic flats and long, even runs. Both offer limited rods, steady hatches, and shots at larger trout. [web:131][web:132][web:135]
DePuy’s Spring Creek
Roughly three miles of riffles, deep runs, glassy flats, and a spring‑fed pond. Widely considered one of the finest spring creeks anywhere and arguably the valley’s best winter fishery. Migratory trout from the Yellowstone move in to feed and spawn, and the variety of structure lets us pivot with light, wind, and hatches. [web:130][web:132][web:138]
Armstrong Spring Creek
About 1.3 miles of private water on the O’Hair Ranch with lush banks, glassy currents, and gentle riffles. It fishes like a dry‑fly classroom: sight‑nymphing, small dries, and emergers over educated trout. PMD and Baetis hatches are the heart of the program, with well‑placed duns and cripples bringing up very large fish. [web:131][web:135][web:140]
Learn More from DePuy’s & Armstrong’s
Both ranches maintain detailed websites with current rod fees, booking policies, and photo galleries. We coordinate guide days around their availability and rules so your trip runs smoothly. [web:127][web:126][web:131]
Skill Levels & Expectations
Newer Anglers
You do not need to be an expert to fish spring creeks, but patience helps. Winter and early spring offer softer fish and lower rod fees, which is when we often bring newer anglers here. We focus on casting basics, mending, and reading lanes, and choose water where fish are feeding steadily rather than only the hardest heads in the creek. [web:129][web:132][web:138]
Intermediate & Advanced
If you enjoy problem‑solving and small‑fly detail, these creeks are ideal. Tiny adjustments to fly choice, size, angle, depth, and drift all matter. Armstrong’s flats demand precise dry‑fly work, while DePuy’s mix of riffles and runs lets us tune difficulty up or down. [web:126][web:128][web:131][web:132]
What a Spring Creek Day Looks Like
Spring creek trips are walk‑and‑wade. A typical full day covers one to two miles of water with lots of stopping, glassing, and planning shots. On DePuy’s we use the three wood‑stove huts as home bases in cold months; in summer we adjust start times to match hatches and avoid the brightest, busiest hours. [web:132][web:138]
We rig rods for nymphing, emergers, and dries and switch as conditions change. You will spend a lot of time watching fish rather than just casting, with the goal of leaving understanding how these creeks work and how that translates to your home water.
Winter & Spring Creek Info
When the Yellowstone is frozen or too cold, DePuy’s and Armstrong’s often fish best. Our winter and shoulder‑season program focuses on the warmest hours of the day, sight‑fishing to trout feeding on midges, scuds, and sowbugs in clear water. Lower winter rod fees and fewer anglers make this one of the best times to learn spring creeks. Full details live on the Winter & Spring Rate page. [web:126][web:132][web:135][web:138]
If you already have dates in mind, the simplest step is to hold a day on the calendar and decide between DePuy’s and Armstrong’s as conditions get closer. If you are still choosing between spring creeks and rivers, send your dates, lodging, and rough goals and we will point you toward the best fit.
Rod Fees & Availability
- Rod fees vary by season and are highest during peak PMD hatches in late June–July. [web:127][web:130]
- Only a limited number of rods are allowed each day; prime summer dates can book a year out. [web:130][web:133]
- Winter and shoulder seasons offer lower fees, fewer people, and excellent learning conditions. [web:126][web:132]
Ready to Fish?
- We handle rod reservations with the ranch and match your dates to DePuy’s, Armstrong’s, or another water.
- Instruction can be beginner‑friendly or highly technical, depending on what you want from the day.
- You will leave with a clearer picture of how to fish technical water anywhere you go next. [web:135][web:138]
