When people think about fly fishing in Utah they think of the Provo River. The Provo has some of the highest fish density in the state but also the most guides, and fisherman and most educated fish as well. I like to get away to where I don’t see as many fisherman but still catch good sized decent fighting fish. This would be to Weber River that flows right outside the Salt Lake City area. The Weber is divided into three different sections. These sections are the Upper, Middle and Lower. Each section has its positives and negatives and it all depends on what you’re goals are for your trip on where you would decide to fish.
The Upper section flows into Rockport Reservoir. Above Rockport there is a lot of private land but you can still get into quite the good rainbow or brown trout. There are some good sections right in the mouth of the lake. You can catch rainbows leaving the lake to spawn in the spring and there is a nice parking area next to a campground that is a short walk to the river. You’re closer to places in the Unitas such as Smith and Moorehouse Reservoir which has grayling, cutthroat, tiger trout as well so you can change your plans easily if the fish aren’t biting or the water is too high
The middle Weber starts below the spillway at Rockport Reservoir and flows all the way down to Echo Reservoir. The nice part about this portion of the Weber is it was recently deems navigable and as long as you are in the stream bed you are not trespassing. There are several walk in access ladders along the fence line and you are able to get a free walk in access code at the Utah DNR website. The majority of the fish you will find on this stretch of the river will be brown trout. Most of the fish I have caught on this stretch of the river seem to be bigger in the average size but fish catch rate and density isn’t as good as other stretches. I would encourage you to go during the week because on weekends you’ll probably bump into a couple people and have to do some leap frogging along the way. If you are fishing this portion of the river please practice catch and release  because the browns in there are naturally reproducing. The spillway right below Rockport used to have a decent amount of big browns below it until one weekend a group came in there with worms and each person pulled their limit out and that stretch has not recuperate from the stringer full of big fish taken out of there
The last section is the lower Weber and flows from Echo Reservior till it meets with the Ogden River and continues on. This section carries mostly browns higher up but as you get down farther into the canyon you can find cutthroat trout. If you are doing your Utah cutthroat slam you can use a cutthroat caught in this river as either a Bonneville or Bear River. It is required for all Cutthroat Trout to be released back into the river and none can be kept. In the summer time you’ll find this section of river used by people floating down on inner tubes which can be quite frustrating. The fish numbers here are a lot better but the fish size is significantly smaller and since its closer to a dense populated area you have more chance of running into people.
So for the fisherman that is looking for a place that is less crowded with less guides and bigger fish the Weber River is the place to go. If you decide to use this river please keep it a great fishery by releasing your fish and not fishing the “Reds” (spawnign brown trout beds) in the fall. All sections of the river will contain Whitefish as well which can put up quite the fight and grow to decent sizes. They are in high numbers in the Weber and are nicknamed the Rocky Mountain bonefish for how well they fight.