Wade, bank, and floatLimited data
Use the live sources and what you see at the river before choosing an approach.
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Fly fishing report · West
North St. Vrain
A Button Rock-focused North St. Vrain planning page built around walk-in access, permit-aware fishing, clear-water tactics, and Front Range backup decisions.
Check flow & weatherToday's fishing decisionSome live data available
11
Skip today
Verify conditions before committing.
The NWS forecast is near 90F. Without live water temperature, heat risk needs a conservative check.
Best supported approachCheck the water first
Watch nextHeat: The NWS forecast is near 90F. Without live water temperature, heat risk needs a conservative check.
Updated Aug 3, 12:23 AM UTCCurrent conditions checked regularly
Before choosing how to fishCheck the water first
There is not enough reliable current information to recommend wading, bank fishing, or floating.
Check before you drive
Current flow and weather.
Look at whether the river is rising or falling, then check wind, rain, and storms. These can change both safety and fishing.
Loading current flow and weather.
Before you rely on this report
How current is this report?
Conditions can change quickly. Check these dates before you decide to fish, and open the official source when safety or rules matter.
- River conditions
- Checked Aug 2, 2026, 8:23 PM
- Fishing guidance
- Reviewed May 31, 2026
- Public access
- No reviewed map pin available
- Rules and closures
- Official rule links checked
Medium confidence in the current score inputs.
7 sources are listed below for you to open.
3 public access records are listed. Private spots are never shown.
Source checked Jul 30, 2026
Plan your access
Know where you can enter.
These are public parking, launch, trail, or recreation areas—not secret fishing spots. We never show an angler's private pins, notes, or photos here.
- 0
- Shown on map
- 3
- No map pin
Location checkedDescription only
01No map pin
Area description
Button Rock Preserve entrance and fishing pier
Best official starting point for creek access and preserve orientation.
Restrictions and seasonal notes
Button Rock is walk-in only beyond the gate, and the parking lot can close when it fills.
Creek fishing and Ralph Price Reservoir fishing are not the same plan. The reservoir has a separate permit structure and season.
02No map pin
Walk-in / wade
Longmont Reservoir side of the preserve
Useful for nearby walk-in water and mixed preserve scouting close to the entrance.
Restrictions and seasonal notes
Button Rock is walk-in only beyond the gate, and the parking lot can close when it fills.
Creek fishing and Ralph Price Reservoir fishing are not the same plan. The reservoir has a separate permit structure and season.
03No map pin
Area description
Ralph Price Reservoir approach
A two-mile hike and a separate permit context if you choose the reservoir instead of the creek.
Restrictions and seasonal notes
Button Rock is walk-in only beyond the gate, and the parking lot can close when it fills.
Creek fishing and Ralph Price Reservoir fishing are not the same plan. The reservoir has a separate permit structure and season.
How to fish it
Plan the walk and the permit rules before you plan the flies.
The North St. Vrain below Button Rock is most useful when you treat it as a walk-in creek with clear access boundaries, pressure-aware presentations, and a backup option if the preserve is busy or the water is running too hard.
- Use RiverReports for quick flow context, then match the day to Button Rock Preserve access rules and the forecast.
- The City of Longmont preserve page gives the clearest public access and seasonal-use framework for this reach.
- Fish the creek quietly with short drifts and light rigs; the walk-in setting does not make the trout careless.
- Do not confuse creek access with the separate Ralph Price Reservoir permit program when choosing where to spend the day.
Why the score looks this way
HeatLowers score
The NWS forecast is near 90F. Without live water temperature, heat risk needs a conservative check.
FlowUse caution
RiverReports is linked for the flow chart, but this page does not have a structured live flow value the score can read automatically. Treat the rating as conservative and open the chart before committing.
Public alertUse caution
An Air Quality Alert is active near this forecast point, so the score is capped at caution until smoke and access conditions are checked. NWS alert: Air Quality Alert issued August 2 at 4:10PM MDT by NWS Denver CO.
SeasonHelps score
Summer: Primary season for early dries, caddis, terrestrials, and quick morning sessions.
Fishing usefulnessHelps score
Skip when the preserve lot is full, summer heat is building, or the creek is too pushy to fish from safe edge positions.
Read the water
What changes the plan.
Late spring after runoff begins settling, summer mornings, and early fall are usually the best planning windows. Preserve crowding and exposed sunny afternoons can narrow the useful fishing window faster than the map suggests.
Low clear water
Use fine tippet, stay low, and fish smaller dries or light droppers along seams and banks.
Moderate stable flow
Best all-around condition for dry-dropper fishing and short nymph drifts.
High or pushy flow
Treat the creek as a bank-first scouting day or move to a safer backup if footing disappears.
Hot sunny afternoons
Fish early, monitor temperature, and shorten handling on pressured Front Range trout water.
Your trip plan
Know when to go—and when to skip it.
Best flows
Stable clear flows that leave seams and bank pockets readable without forcing aggressive crossings.
When to skip
Skip when the preserve lot is full, summer heat is building, or the creek is too pushy to fish from safe edge positions.
Local plan
Get there early, fish creek water near the entrance first, decide whether the walk farther in is earning value, and keep Big Thompson or Boulder Creek ready as backups.
Backup water
Big Thompson, Cache La Poudre, or Boulder Creek are better pivots when Button Rock access, heat, or crowds narrow the day.
Hatches & flies
Bring a flexible box.
TimingWhat to watchUseful flies
SpringMidges, BWOs, and caddisRS2, zebra midge, BWO emerger, small caddis pupa
Fly pattern · report suggests “RS2”RS2Start with the beadless architecture: two dark-dun Microfibett tails separated behind a slim, tightly twisted and visibly segmented dubbed abdomen; a fuller thorax; and saddle-hackle web clipped into a short angled wing bud. Rim Chung's original-style form uses natural beaver dubbing and hackle web. CDC- or Antron-wing ties, beads, curved hooks, flash, and tailless Avatar-style flies must remain labeled variations.See photos & how to fish it ↗
Fly pattern · report suggests “zebra midge”Zebra MidgeLook for a very slim tapered thread body, evenly spaced contrasting wire rib, a small bead, and no tail or wing. The reviewed classic is black with silver wire and a silver bead. Red, olive, brown, glass-bead, jig-hook, resin-coated, or tailed forms must remain labeled variations rather than replacing the classic identity.See photos & how to fish it ↗+ 2 more reviewed guides in the Fly Box SummerCaddis, PMDs, yellow sallies, and antsElk hair caddis, PMD dry, yellow stimulator, foam ant
Fly pattern · report suggests “Elk hair caddis”Elk Hair CaddisLook for a tented elk- or deer-hair wing, clipped hair head, dubbed body, rib, and hackle palmered along the body. The body color should be labeled because tiers often match different natural caddis colors.See photos & how to fish it ↗
Fly family · report suggests “PMD dry”Pale Morning Dun PatternsPMD names an insect group, not one fly. Pale nymphs, trailing-shuck emergers, upright or low-riding duns, cripples, and spent-wing spinners stay visibly separate.See family guide ↗+ 2 more reviewed guides in the Fly Box Late summerTerrestrials and evening caddisBeetle, ant, hopper, soft hackle
Fly family · report suggests “Beetle”Beetle PatternsBeetle flies range from simple foam shells to hair-bodied and sunken forms. A rounded back and compact profile distinguish the family from ants and hoppers.See family guide ↗
Fly family · report suggests “ant”Ant PatternsAnt patterns can be foam, fur-bodied, winged, or sunken. The narrow waist and paired body lobes matter more than one material recipe.See family guide ↗+ 2 more reviewed guides in the Fly Box FallBWOs and midgesParachute BWO, RS2, zebra midge
Fly family · report suggests “Parachute BWO”Blue-Winged Olive PatternsBWO describes a hatch group, not one fly. Nymph, emerger, dry, cripple, and spinner profiles must stay separate because they occupy different parts of the water column.See family guide ↗Fly pattern · report suggests “RS2”RS2Start with the beadless architecture: two dark-dun Microfibett tails separated behind a slim, tightly twisted and visibly segmented dubbed abdomen; a fuller thorax; and saddle-hackle web clipped into a short angled wing bud. Rim Chung's original-style form uses natural beaver dubbing and hackle web. CDC- or Antron-wing ties, beads, curved hooks, flash, and tailless Avatar-style flies must remain labeled variations.See photos & how to fish it ↗+ 1 more reviewed guide in the Fly Box 01
Fish the first good-looking water you can reach legally because the creek near the entrance can be as useful as farther walk-in sections.
02
Stay off obvious banks and keep the first cast clean; preserve trout see plenty of hikers and anglers.
03
Use the creek for precision rather than distance, especially when other visitors are moving through the same corridor.
04
If the preserve parking lot is full or summer heat is building, pivot early instead of treating the walk as sunk cost.
Rules & closures
Check the official rules before you go.
Open the agency page to confirm the exact river section, species, season, tackle rules, limits, and emergency closures.
Official links checkedRules for this river or sectionNo special rule found
We did not find a special rule for this river.
We checked the state source but did not find a clearly supported exception for this river. Check the official rules for the exact section you plan to fish.
Rules checkedJul 30, 2026
Report a correction ↗Always follow the official rule
This summary helps with trip planning. The linked agency rule is the one you must follow.
Updates from anglers
What anglers are seeing.
Recent observations from general areas of North St. Vrain. We review every update before it appears and never publish exact fishing spots, private access details, or photo locations.
Angler updates are not loading right now.
You can still use the river plan above. Check back later for recent observations from other anglers.
Where this report comes from
Open the sources we checked.
Fishing guidance checked: May 31, 2026
Site check: Jul 14, 2026. We regularly test report links, live scores, flow and weather data, and page loading. The content date changes only when the fishing guidance or its sources change.
flowRiverReports: North St. Vrain below Button Rock ReservoirsafetyNWS forecast point below Button RockaccessCity of Longmont Button Rock PreserveaccessCity of Longmont fishing informationregulationCity of Longmont Ralph Price Reservoir Fishing ProgramregulationColorado fishing regulationsregulationColorado fishing licenses and dates
Common questions
Before you leave.
Do I need a special permit to fish the creek?+
For the creek, start with a valid Colorado fishing license. The separate special permit applies to Ralph Price Reservoir inside Button Rock Preserve.
Is the best fishing far inside the preserve?+
Not always. Water close to the entrance can fish well, especially when you can work it quietly before foot traffic builds.
What is the biggest planning mistake here?+
Mixing up preserve access rules, reservoir permit rules, and creek strategy. Sort those out before you choose flies.