Union Reservoir
Union Lake, just east of Longmont, is proving to be one of the states premier wiper lakes offering good fishing for bass and walleye as well. Located near Longmont
Fish Species in Union Reservoir:
Union Reservoir on FishExplorer has 452 historic conditions reports, 301 historic water temperature updates, 186 historic status updates, 303 historic water level updates, available with FxR+.
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Recent Reports
We have cataloged 1,242 reports for Union Reservoir, including detailed updates, temperatures, levels, and lake status.
| Status: | 11.20.24 | |
| Water Tmp: | 07.26.24 | |
| Level: | 04.15.25 |
Conditions Report
Conditions reports for Union Reservoir are available to contributors and subscribers. Create an account or log in, then join FxR+ for a boat-load more on FishExplorer. Last fishing conditions report for Union Reservoir: 04.15.25
Union Photos
There are 22 photos on FishExplorer for Union Reservoir. Join FxR+ to see them all.
Your Trip Journal
Union Reservoir
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Latest Content
Anyone fish Union lately ? (forum) 08.29.23 by Hawaiian Punch
Master Angler Records
This lake has 26 records, including 6 bass, 7 panfish, 8 rough fish, 5 walleye-type species. Master angler data compiled from the Colorado Parks & Wildlife. Join FxR+ for full details.
General Details
Originally called Calkins Lake, the Union Reservoir was carved out during the last glacial age and is one of only a few natural lakes in Colorado. In 1903, the Union Ditch Company began drilling a tun... Log in for additional details...
Extra Details for FxR+
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Regs/Info
Log in for additional details... We have more information including 5 links, file attachments, and/or contacts, plus details for:
- fishing regulations
- ice fishing regulations
- OHV regulations
Camping
No campsites are recorded for this lake.
But there is a short note about camping here or near here is available.
Boating
Directions, Fees, Misc
Managing Agency
City of Longmont350 Kimbark Street
Longmont, CO 80501
303-776-6050
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FishExplorer Region: Boulder/Longmont
Directions
Take I-25 to Highway 119 (Longmont exit). Go west to County Line Road 1. Go north approximately 3/4 ...Fees
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Union Reservoir Stocking Data
Contact the local aquatic biologist for more information on fish stocking. More info...
- Since 1999 Union Reservoir has had 18 stocking events for this species. Register for free and log in for details.
Total # Lbs #/Lb Inches Avg 535,688 769 696.9 682,937 1.27 - Since 2013 Union Reservoir has had 1 stocking event for this species. Register for free and log in for details.
Total # Lbs #/Lb Inches Avg 3,008 - 10,673 3.55 - Since 2013 Union Reservoir has had 2 stocking events for this species. Register for free and log in for details.
Total # Lbs #/Lb Inches Avg 24,001 22 1,077.2 37,696 1.57 - Since 1995 Union Reservoir has had 18 stocking events for this species. Register for free and log in for details.
Total # Lbs #/Lb Inches Avg 456,882 4,721 96.8 1,386,825 3.04 - Since 1995 Union Reservoir has had 21 stocking events for this species. Register for free and log in for details.
Total # Lbs #/Lb Inches Avg 1,133,306 343 3,299.6 667,255 0.59 - Since 2001 Union Reservoir has had 7 stocking events for this species. Register for free and log in for details.
Total # Lbs #/Lb Inches Avg 21,110 490 43.1 69,552 3.29 - Since 2021 Union Reservoir has had 2 stocking events for this species. Register for free and log in for details.
Total # Lbs #/Lb Inches Avg 24,030 29 821.8 29,704 1.24 - Since 2011 Union Reservoir has had 9 stocking events for this species. Register for free and log in for details.
Total # Lbs #/Lb Inches Avg 950,366 206 4,610.5 594,018 0.63 - Since 2003 Union Reservoir has had 4 stocking events for this species. Register for free and log in for details.
Total # Lbs #/Lb Inches Avg 21,000 131 159.7 45,937 2.19 - Since 1996 Union Reservoir has had 10 stocking events for this species. Register for free and log in for details.
Total # Lbs #/Lb Inches Avg 13,030 878 14.8 97,412 7.48 - Since 2006 Union Reservoir has had 10 stocking events for this species. Register for free and log in for details.
Total # Lbs #/Lb Inches Avg 3,835,578 36 106,721.7 1,185,864 0.31
Weather, Sun & Moon
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Our weather data is specifically designed for pertinent fishing conditions leading up to current time, forecast for the near future, and are interpolated with advanced models for the specific location of this lake based on exact coordinates, between weather stations, not for a single weather station that may be far away. These tools are available with FxR+.
Barometric Pressure Forecast Data for Union Reservoir
Lake Imagery/Maps
We have 4 alternate images and/or maps for Union Reservoir
Lakes & Rivers Nearby
Top Reporters
| # | Last Rpt | NickName |
| 310 | 3/8/2021 | jshanko |
| 84 | 5/21/2013 | never summer |
| 71 | 3/19/2009 | love2flyfish |
| 62 | 4/15/2025 | wah |
| 48 | 8/28/2023 | Killerfihser |
| 47 | 7/26/2024 | Matt |
| 34 | 5/16/2019 | fish234 |
| 27 | 6/10/2016 | bardkin |
| 20 | 7/15/2019 | Darrell G |
| 15 | 5/27/2014 | phidoux |