Fishing at Ish Reservoir, Boulder County, Colorado

• Overview

  Ish Reservoir is one of the Boulder County waters in Colorado. The setting is farm and woodlot on every side. This is sizeable water at about 317 acres, and a boat opens up most of it. At about 3.2 miles of edge, most people work one arm at a time. Size puts it in the front rank of our Boulder County list. The closest town, Berthoud, is 3.5 miles distant. Further out sit Mead (5.2 miles) and Longmont (6.3 miles). This one sits near enough to a boundary to be worth checking.

• Where to Fish on Ish Reservoir

  There is no published depth for this one, so start shallow and work out. Rip-rap along the wall holds fish that the open bank never does. Look for where the old bank line still shows under the surface. Public occurrence data for Boulder County names black-spotted cutthroat trout, brook trout, brown trout and bluegill. What holds for the county may not hold for this water. Ish Reservoir gives up its fish to patience rather than distance.

• Seasonal Patterns

  The year swings from about 28°F in January to roughly 72°F in July. Mild ends to the year keep the season long. Cover comes and goes, so treat it with suspicion rather than trust. March through May is the strongest run, with October and November a second stretch. Plan around that when you fish Ish Reservoir.

• Tackle & Baits

  Ownership and access are not documented in what we hold. Mapping shows no built access close by; expect to walk in from wherever you can leave the car. Light line and small metal for the trout; a fly rod earns its place on calm evenings. Parking space is the usual limit rather than the bank itself. Night access is frequently treated as a separate matter. Divide Reservoir sits 1.3 miles off and takes the overflow. Confirm before you fish Ish Reservoir.