Fish Explorer Logo
Colorado Fishing
Colorado Fishing  
Login Usr:Psd:
No account? Register now...
spacer spacer
The lake page you are viewing is showing limited information. Log in to gain detailed access.

Union Reservoir

Status:  Log in or Register... 09.16.23
Water Tmp:  09.16.23
Level:  09.16.23
  Conditions Report
Conditions reports for this lake are available when logged in. Last Conditions Report for Union Reservoir: 05.18.24
Union Reservoir on FishExplorer has 444 historic conditions reports, 300 historic water temperature updates, 184 historic status updates, 300 historic water level updates, available to subscribers.
Lake Skipper(s):
Regional Editor:
Fish Species in Union Reservoir:
Black Bullhead, Black Crappie, Blue Catfish, plus 14 more... (Log in for full fish species list)
Log in to view campgrounds & boat ramps...
  • Add Fish
  • Weather Hist
  • Forecast
  • Sun & Moon
Google Map
Topo Map
3-D View
Sat. View
Map/Ftr Pic
Member Photos
photo by eholm photo by Silver Jack photo by The Dooze photo by kd0gmy photo by TADA32 photo by TADA32 view more photos...
There are 22 photos on FishExplorer for Union Reservoir. Subscribe to see them all.
Union Reservoir
Managing Agency: Surface Acres: Capacity AF: Elev:
City of Longmont Log in to view full details on lakes and rivers on

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 tunnel to release water into the St Vrain River. According to Colorado water law, that made Union a tru... Log in for additional details...

Additional Details for Subscribers:

Subscriber-only writeup available (length: 737 words). Subscribe

Getting there:

Take I-25 to Highway 119 (Longmont exit). Go west to County Line Road 1. Go north approximately 3/4 of a mile and turn right at the sign for Union Reservoir. The entrance is about 1/2 mile up this road on your left.

Additional Lake Information for Union Reservoir:

Log in for additional details...
Links, File attachmenmts, Contacts = 5
Special Regs
Ice Fishing Regs
OHV Regs
Recent Related Content
Anyone fish Union lately ? 08.29.23 by Hawaiian Punch
Union res. 7-3 07.03.20 by Eyefishing
Shout out to J Shanko 05.27.20 by hunter creek
Crappie 09.02.18 by BioWyo
It finally happened... 08.12.18 by catman82
Union Master Angler Awards
Aggregated Master Angler records are available for FxR+ subscribers.
There are 18 Master Angler records available on FishExplorer to view associated with Union Reservoir.
Upgrade to FxR+
Conditions History
Subscribe to FxR+ for private journal history, private fish log, and historical report archives.
Union Reservoir Stocking 2021 to 2023
Log in with your free account to view stocking data for available lakes on
Boat Ramps
Log in for detailed camping and boat ramp information.
Lake Class: 1
Operation Game Thief
Call to report illegal fishing/hunting:
Email CPW