Big Thompson River

Big Thompson River

Difficulty Beginner/Intermediate
Ideal Days To Fish 4/1, 4/2 & 4/3

Weekly Report

Report DateMarch 30, 2023

The Big Thompson below Lake Estes is experiencing daily fluctuations in flow. Fluctuations of 5-15 cfs isn’t necessarily enough to have a material impact on the fishing but it’s still something to keep an eye on. Warmer weather has helped break up a good amount of the ice in the lower section through the canyon. While you’ll still find some ice shelves, there is enough open water to fish. Targeting pronounced pools and runs with a double or triple nymph rig is the most effective tactic right now but don’t overlook slower riffles, pocket water and transitions during hatches and on warm afternoons. Trail a midge pupa in the morning and late afternoon/early evening. During the early afternoon, trail a baetis emerger. Top Secret Midges, Mercury Black Beauties, Mercury Midges, Blue Poison Tungs, Chocolate Foam Back Emergers, RS2s and Mercury Baetis are all solid options. For your lead pattern, Mini Leeches, eggs, baetis larva, flashy attractors and searcher patterns are working well. Aside from nymphing, dry fly action is starting to pick up. Midges are sporadically hatching after 10 am with the strongest hatches occurring during the afternoon and early evening. Matt’s Midges, Griffiths Gnats and Parachute Adams in size 18 – 22 will attract trout looking up.

Recommended Flies

River Flow

Flow Region

Detailed River Info


The Big Thompson, commonly referred to as the Big T, is a beautiful river that originates high in Rocky Mountain National Park. This small-medium sized river flows through Rocky Mountain National Park and the town of Estes Park before feeding into Lake Estes. Below Lake Estes, the river continues along Highway 34 through Drake, eventually making its way to the town of Loveland. The Big T flows through various types of terrain, offering anglers a variety of scenic and fishing opportunities. The stretch of river that flows through Rocky Mountain National Park is in an open meadow setting and contains brown trout, rainbow trout, brook trout and if you’re lucky, greenback cutthroat. Below Lake Estes, anglers will find themselves in a canyon setting dominated by pocket water with a select number of deep pools and runs. Brown and rainbow trout in the 10 – 12” range can be found in this stretch.


The Big Thompson is a diverse river that is friendly to anglers of all skill sets. The stretch that flows through Moraine Park in Rocky Mountain National Park is highly sought after during the summer months. During the summer, this stretch tends to see a lot of foot traffic, so stealthy fishing is required to not spook the trout. Fishing dry and dry dropper setups is the preferred method in Moraine Park. Below Lake Estes, pocket water is prevalent, which may test your ability to fish tight pockets. Nymphing is a productive method year-round, while dry and dry dropper setups are productive during the summer and fall. Overall, the ideal time to fish the Big Thompson is during the summer and fall months. However, if you’re looking to fish during the winter, the section directly below the Lake Estes/Olympus Dam is classified as a tailwater and usually remains ice-free.

River Access

The Big Thompson has many access points with varying levels of difficulty. In order to fish Moraine Park, anglers will need to purchase a $25 National Parks day pass. Moraine Park is located just under 3 miles from the Beaver Meadows Entrance Station on the south side of Estes Park. Below Lake Estes, anglers can access the tailwater section via a public park on Mall Rd. Downstream of the tailwater, there are a number of pull offs along Highway 34 that anglers can use to access the river.  Be conscious of private property when fishing along Highway 34. In general, the bank that borders the road is public and the property along the far bank tends to be private.