Union Reservoir Fishing Guide - Longmont
Private Trip
Lakes/Reservoirs/Ponds Fishing
Target wiper and walleye at Union Reservoir near LongmontThreehour guided lake fishing trip accommodates one guestNowake peaceful waters ideal for beginners and families
Looking for a solid fishing trip that won't eat up your entire day? Union Reservoir just outside Longmont delivers exactly what you're after. This no-wake lake sits pretty in northern Colorado and has earned its reputation as one of the region's most consistent producers of wiper and walleye. With Brad Petersen Outdoors, you'll get three hours of focused fishing time with someone who knows every contour, drop-off, and sweet spot this water has to offer. Whether you're new to the sport or just want to dial in your technique, this private guided experience gives you the personal attention that makes all the difference between coming home with stories and coming home with fish.
Union Reservoir spans about 750 acres of prime fishing water, and the no-wake rule keeps things peaceful while you work the productive zones. You'll launch early enough to hit the morning bite, when fish are actively feeding and the water temperature is just right. The lake sits at around 5,000 feet elevation, which means cooler water temps that hold oxygen well and keep fish comfortable year-round. Your guide knows the seasonal patterns here like the back of his hand - where the thermoclines set up in summer, which structure holds fish during cold fronts, and how weather changes affect fish behavior. The shallow bays warm up first in spring and hold baitfish, while the deeper main lake areas provide summer refuge when surface temps climb. This isn't a massive body of water, so you'll spend more time with lines wet and less time running between spots.
Union Reservoir fishing calls for versatility, and your guide comes prepared with tackle suited to whatever the fish are doing that day. For wiper, you'll often work vertical jigging spoons and blade baits around suspended schools, especially when they're chasing shad in open water. Live bait presentations with nightcrawlers and minnows produce consistently, particularly for walleye that hug bottom structure during daylight hours. The bass fishing here responds well to soft plastics worked around submerged timber and rock piles, while trout often fall for trolled spinners and small spoons along drop-offs. Your guide brings both spinning and baitcasting setups in various weights to match conditions - lighter tackle for finesse presentations and heavier gear when fish are aggressive or you need to work deeper water. The beauty of a guided trip is having someone read the water for you, adjusting tactics based on weather, water clarity, and fish activity rather than sticking to one approach all day.
Union Reservoir's bluegill population provides steady action throughout the warmer months, with fish averaging 6-8 inches and the occasional hand-sized specimen that'll put a serious bend in light tackle. These panfish spawn in the shallows during late spring, making them easy targets for anyone wanting to learn proper presentation and hookset timing. Largemouth bass here aren't huge, but they're aggressive and fun to catch, typically running 12-16 inches with some pushing into the 3-4 pound range. They love the submerged structure and weed edges where they can ambush prey. White bass, or wipers as locals call them, school up heavily and provide some of the most exciting fishing when you find them actively feeding. These hybrid stripers fight hard for their size and often travel in packs, meaning multiple hookups when you dial in their location. Walleye represent the premier table fare, with most fish running 14-18 inches and providing excellent eating. They're structure-oriented and bite best during low-light periods, making early morning starts worthwhile. Rainbow trout add variety to the mix, especially during cooler months when they become more active in shallow water and respond well to small spinners and bait presentations.
Three hours gives you enough time to work different areas and techniques without turning fishing into an endurance test. Union Reservoir delivers consistent action for anglers who want quality fishing close to the Front Range, and having a guide who knows the water eliminates the guesswork that can make or break a trip. You'll learn techniques that work here and gain confidence in reading water conditions that'll serve you well on future fishing adventures. The single-angler format means personalized instruction and the flexibility to focus on whatever interests you most, whether that's mastering specific techniques or simply putting fish in the boat. This top-rated northern Colorado fishing experience books up during peak seasons, so grab your spot while you can and get ready to see what Union Reservoir has been holding under its surface.
Our 2004 18' Lund with a 135HP Mercury is built for serious fishing on Union Reservoir's calm waters. This sturdy aluminum hull handles the lake's conditions perfectly while staying quiet enough not to spook the wipers and walleye lurking below. The wireless trolling motor lets you position silently over structure where fish hold, while the GPS keeps you on productive spots trip after trip. The fish finder is your underwater eyes, showing you exactly where those quality walleye are suspended and helping you target the best depths. At 38 knots max, you'll reach the hot spots quickly, then settle into productive fishing mode. With space for up to 4 anglers, there's plenty of room to work your lines without tangling. This boat's proven track record on northern Colorado waters means more time with your line wet and less time dealing with mechanical issues.
Lepomis MacrochirusBluegill are scrappy little fighters that average 8 inches but can surprise you up to 16 inches. These colorful panfish love shallow areas with weeds and cover, especially around fallen logs or docks. You'll find them in schools of 10-20, making for steady action once you locate them. Spring through early summer is prime time when they're spawning in the shallows. What makes bluegill special is their willingness to bite almost anything - perfect for kids and beginners. They put up a surprisingly good fight for their size and taste great on the table. Use small hooks since they have tiny mouths, and try a simple bobber rig with worms. Here's a local tip: look for those circular spawning beds in shallow water during late spring - that's where the action heats up.
Micropterus SalmoidesLargemouth bass are the heavyweight champions of Union Reservoir, typically running 12-24 inches and 1-4 pounds. These ambush predators love structure - fallen trees, weed edges, and rocky areas where they can hide and strike. They're most active during low-light periods at dawn and dusk, but you can catch them all day if you know where to look. Bass are aggressive fighters that'll jump and run, making every hookup exciting. Spring through fall offers the best action, especially when water temps hit that sweet spot around 70 degrees. They're also excellent eating when prepared right. The key here at Union is working those weed lines slowly with soft plastics or crankbaits. Pro tip: don't set the hook too hard on the initial strike - let them take it and then drive it home.
Oncorhynchus MykissRainbow trout are beautifully colored fighters averaging 8-16 inches with that distinctive pink stripe along their sides. These cold-water fish prefer the deeper, cooler sections of Union Reservoir, especially near inlet areas with good oxygen flow. Early morning and late evening provide the best action, particularly in spring and fall when water temps are ideal. Trout are famous for their acrobatic fights - they'll jump, run, and test your drag like no other fish their size. They're also premium table fare with delicate, pink flesh that's hard to beat. Look for them in 15-30 feet of water around structure or suspended in open areas. Small spinners, spoons, or PowerBait work well, but fly fishing with nymphs can be deadly effective. Local secret: focus on areas where streams feed into the reservoir - trout often hold there waiting for food to wash down.
Sander VitreusWalleye are Union Reservoir's crown jewel - golden-colored predators that can reach 20+ pounds and stretch over 30 inches. These nocturnal hunters have distinctive glassy eyes that help them see in low light. During the day, they stick to deeper water around 15-25 feet near rock piles and drop-offs, then move shallow at dusk to feed. Fall through early spring produces the best fishing when water temps cool down. Walleye are prized for their incredible table quality - firm, white, flaky meat with virtually no fishy taste. They fight with strong, steady runs rather than flashy jumps. The trick is fishing slowly with live bait rigs or jigs tipped with minnows right along the bottom. Here's what works at Union: focus on the rocky points and underwater humps during evening hours - that's where the big ones cruise for an easy meal.
Morone ChrysopsWhite bass are silver speedsters that typically measure 10-12 inches and pack a serious punch for their size. These schooling fish roam open water but concentrate near drop-offs and structure. Spring is prime time when they move shallow to spawn, but they bite year-round if you can locate the schools. What guests love about white bass is their aggressive nature - when you find one, there's usually a whole school nearby. They're also some of the best eating fish in the lake with firm, flaky white meat. Look for them in 10-20 feet of water, especially where rocky bottoms meet deeper areas. Small jigs in white or black work great, but live minnows are hard to beat. Local tip: when you see diving birds working the surface, get there fast - they're likely feeding on baitfish with white bass below.
Colorado