Simply put, July is a prime time to fish in Yellowstone National Park. As run-off subsides early in the month, anglers have a chance to target fish that have not seen flies since the previous fishing season. Both water levels and temperatures are at prime levels and the hatches are both thick and varied. The waters of the Madison drainage become too warm to fish and the main focus for anglers shifts to the Yellowstone River drainage in the northern reaches of the park. Small streams and alpine lakes also become options as the snow rapidly recedes from the high country. Outside of rivers that are thermally heated, virtually the entire park will be fishing well, giving the angler 2.2 million square miles of options. Let’s take a look at some of the best choices.
Yellowstone River
Fishing on the Yellowstone River starts off with a bang, as both salmonflys and golden stones will begin hatching as soon as the river clears right around the first of the month. The hatches will start in the Black Canyon down by Gardiner and gradually move upstream all the way into the Grand Canyon between Tower and Canyon Village. Access to both canyons is hike-in only, with lengths ranging from ¼ mile to full on multi-day expeditions. The easiest access point is the Tower Falls trail but consulting a park map will give you plenty of options. The large stoneflies usually go strong for a full two weeks before giving way to smaller insects such as caddis and yellow sallies. Attractor dries become very important by the end of the month. If the dry fly fishing is slow, which can be the case early in the morning or during the mid-day heat, try stripping a streamer down deep. One thing to always keep in mind when planning to fish the Yellowstone is that the Lamar River is a major source of dirty, muddy water during runoff and after summer thunderstorms. The Yellowstone will often be in perfect shape above the Lamar confluence and completely unfishable below.
Slough Creek
Slough Creek, a world famous meadow stream known for its large cutthroat trout, is at its best in July. The fishing is in full swing by the first or second week of July with prolific mayfly hatches including PMD’s and all 3 species of Drakes. Caddis, midges, and the occasional wayward stonefly round out the buffet. As July progresses, terrestrial insects including hoppers, ants, and beetles become the most productive flies. Slough Creek is divided into a series of meadows, with the Lower Meadow and First Meadow being the most popular day trips. The Lower Meadow, which is partially road accessible, extends from the campground down to the confluence with the Lamar while the First Meadow is a 2.5 mile hike above the campground. The average fish runs 14”-18”, with a few over 20”. Slough is fished very hard day in and day out, and the fish become very wary in the slow, gin clear water. However, this does not happen overnight and the fish are much less wary at the start of the summer than the finish. Bring 10 to 12 foot leaders in 4X and 5X, along with your “A” game and you will have a shot at some trophy native Cutthroat Trout.
Lamar River
The Lamar is another of Yellowstone Parks’ famous meadow streams inhabited by good sized Cutthroat Trout. The river is typically the last in the park to clear from spring runoff, usually around the middle of July. Green Drakes and Pale Morning Duns will be the primary hatches, with terrestrials quickly becoming your key flies as the summer heats up. Like Slough Creek, the Lamar is fished quite heavily but the water is not quite as clear and has more pitch to it. Thus, the fish are not as wary but not easy by any means. The most popular stretch of river runs in a large meadow from the Soda Butte confluence downstream about 6 miles to the head of a small canyon. Here, the river runs mostly in site of the road and contains many Cutts from 13”-18”. One trait of Cutthroat Trout, especially those that see a lot of flies, is to rise to the fly extremely slowly. Oftentimes they will suspend themselves just below the fly and drift in sync while they study your offering. Make sure to stay patient and don’t rip the fly away before the fish fully engulfs it. If fish are consistently refusing your fly, try downsizing to a small mayfly or beetle pattern instead of a hopper. Keep in mind that the Lamar muddies quickly after a rain, and may be out of commission for a few days.
Soda Butte Creek
A tributary of the Lamar, Soda Butte Creek displays many of the same characteristics. The major difference, besides being a bit smaller, is that Soda Buttes’ meadows are interspersed with faster, steeper, pocket water sections of creek. While the fish are smaller here, they are much less critical of your fly selection and presentation than in the meadows. Soda Butte tends to clear a few days before the Lamar, but shares the propensity to muddy after any rain. While this can be a serious annoyance to the angler, a couple days of dirty water gives the fish a break and provides relief from the mid-summer heat. As with Lamar, look for hatches of Green Drakes and PMD’s in the meadows and throw terrestrials in the absence of rising trout. Your favorite attractor pattern in a #10 or #12 will work in the pocket water. Soda Butte parallels the Northeast Entrance Road all the way to Cooke City, Montana so access is straightforward.
Gardner River
The Gardner is a much more forgiving stream than the technical meadow fisheries of the Lamar Valley. As July dawns, the salmonfly hatch will be underway below the Boiling River, moving above sometime around the second week of July. The Golden Stone hatch, critically important on the Gardner, coincides with the Salmonflies. While it doesn’t get as much publicity, this hatch is often more intense and longer in duration; the fish can really key in on it. Evenings in July are prime for caddis hatches, especially in sections of river where willows are abundant. Make sure to use an emerger pattern as a dropper off of your dry fly. Absent any hatch, the Gardner offers great attractor dry fly fishing in its broken water. First thing in the morning, especially early in July, nymphing under an indicator will be the most productive method. Choose your favorite stonefly nymph with a caddis dropper and look for the deeper holes. Access to the Gardner is mostly roadside up to the Boiling River, with a hike required upstream.
Small Streams
As the last of the snow melts in the high country, most of the small streams have dropped, cleared, and warmed up enough for productive fishing by the middle of July. I love small stream fishing in the park because it gets you off of the beaten path and away from the crowds. The fish are feisty and rise eagerly to attractor dry flies. Most creeks contain small Brook or Cutthroat Trout, but there will be the occasional surprise if you put your time in. Small streams are too sensitive to discuss publicly, but if you do some studying and put some miles on your boots you will quickly discover some “secret” spots of your own. The best tip I can give is that many small streams are miniature versions of the larger rivers they flow into. Exploring new places is half the fun!