Big Sandwash Reservoir - Altamont, UT

Big Sandwash Reservoir near Altamont is a productive northeastern Utah fishery known for rainbow trout, smallmouth bass, and yellow perch. Covering approximately 1,000 acres, the reservoir has seen facility upgrades in recent years, making it more accessible to anglers.

Rainbow trout are stocked annually and average 12–16 inches. Shore anglers catch them using PowerBait or worms, while boaters troll with spoons and baited rigs along drop-offs. Holdover trout exceeding 18 inches are not uncommon.

Smallmouth bass provide consistent summer and fall action. Bass key in on rocky structure and respond well to plastics and crankbaits. Fish in the 1–3 pound range are typical, with the occasional larger catch.

Yellow perch form dense schools in deeper water during late summer and fall. They’re targeted effectively with small jigs tipped with worm or perch eyes.

A concrete boat ramp and parking lot offer solid access. Winds can be fierce midday, so fish early or late for calmer water and better conditions.

With upgraded access and strong populations of multiple gamefish, Big Sandwash is a great choice for anglers looking for trout, bass, and panfish in one trip.