Potholes Reservoir, WA

About Potholes Reservoir

Potholes Reservoir sits in the heart of central Washington's Columbia Basin, in Grant County, where it was created behind O'Sullivan Dam as part of the Columbia Basin Irrigation Project. It is a large, sprawling impoundment that fluctuates with irrigation demand, and that changing water level helps define how and where anglers fish it through the year. The reservoir is fed largely by seep water and irrigation return flows, and its character ranges from open main-lake basin to the maze of brushy, sandy islands and channels known as the "dunes" or "sand dunes" along the north end.

Anglers across the Pacific Northwest know Potholes as one of the most productive and diverse warmwater and coolwater fisheries in the state. It has a reputation for strong walleye and excellent largemouth and smallmouth bass, along with slab crappie, big yellow perch, bluegill, and a put-and-take trout fishery. The combination of flooded brush, dune islands, weed flats, and deeper main-lake structure means there is almost always something biting somewhere, which is a big part of why it draws both tournament anglers and family fishing trips.

Fish Species

Potholes is a true mixed-bag fishery, and that variety is its calling card. The standout species are walleye and bass, but several panfish and trout opportunities round out the menu.

• Walleye — A signature species here. Potholes produces both numbers of eating-size "eater" walleye and the occasional trophy-class fish, and it is one of the better walleye destinations in the state.
• Largemouth bass — The flooded brush, dune islands, and weedy backwaters of the north end are classic largemouth habitat, and the reservoir is well regarded for quality largemouth.
• Smallmouth bass — Found around rockier structure, main-lake points, and the dam area, smallmouth add a strong second bass fishery.
• Crappie — Black crappie are a major draw, and Potholes is known for producing slabs around brush and submerged cover.
• Yellow perch — Abundant and a popular target, with some areas giving up jumbo perch.
• Bluegill and other sunfish — Plentiful in the weedy, brushy shallows, great for kids and panfish anglers.
• Rainbow trout — Stocked to support a put-and-take fishery, best in the cooler months and the cooler upper water column.

Best Seasons & Times

Spring is one of the most exciting windows. As water warms, walleye move shallow to spawn and become catchable along rocky areas and the dam, while crappie and perch stack up in the brushy north-end shallows. Spring is also prime for pre-spawn and spawning bass moving into the dunes and backwaters. Early morning and late afternoon are productive, and overcast days can extend the bite.

Summer brings warm, stable conditions and a true all-species reservoir. Bass fishing in the dunes and weed edges is excellent at low light, walleye spread out onto main-lake structure and respond well to trolling, and panfish hold around brush and docks. In the heat, focus on early mornings, evenings, and deeper or shaded cover during midday.

Fall can be outstanding as cooling water triggers heavy feeding. Walleye and bass put on the feedbag, perch and crappie school up, and fewer crowds make for relaxed trips. Midday can actually fish well in fall as the water cools.

Winter slows the warmwater bite but rewards anglers who target trout and, when conditions allow, perch and panfish. Water levels are typically drawn down for irrigation storage, which concentrates fish and changes access. Always confirm conditions before a cold-weather trip.

Techniques & Baits

Match your approach to the species and the structure you are fishing — Potholes rewards anglers who adapt.

• Walleye — Bottom-bouncers and spinner/worm harnesses trolled along structure are a staple, as are crankbaits and trolled plugs to cover water. Jigs tipped with nightcrawler, leech, or minnow worked on points, drop-offs, and the dam area produce well, especially in spring.
• Largemouth bass — Work the flooded brush and dune islands with soft plastics (worms, creature baits, senko-style stick baits), weedless rigs to get into cover, and topwater or buzzbaits at low light. Spinnerbaits and jigs shine around brush edges.
• Smallmouth bass — Tube jigs, drop-shot rigs, small swimbaits, and crankbaits around rock and main-lake points are reliable.
• Crappie — Small jigs and curly-tail grubs under a bobber, or live minnows fished tight to brush and submerged cover. Light line and a slow presentation help in clear water.
• Yellow perch and bluegill — Worm pieces, small jigs, and bait under a float around weeds, brush, and docks. Perch often hold near bottom on flats.
• Trout — Trolling spoons, spinners, and small plugs, or still-fishing with floating bait and worms near the surface in cool conditions.

Because water levels swing with irrigation use, pay attention to where the current breaks and where bait concentrates — fish follow the food and the changing edges.

Access & Launches

Potholes Reservoir is a popular, well-developed destination with public boat launches and a state park on its shores, so trailered-boat access is generally good. There are developed launch areas and a nearby state park that serves as a hub for camping and day use, and additional public access points around the reservoir. The north end "dunes" area is a maze of sandy islands and channels best explored by boat, and many anglers run boats from the more developed south-end facilities up into that water. Bank and wade access exists in places, but the reservoir's size and the seasonal water-level changes mean a boat opens up the most water.

Because irrigation drawdown can dramatically change water levels and expose hazards, launch usability and navigation can vary through the season — especially in fall and winter. Check current conditions, ramp status, and any closures before you go, and navigate the shallow dune country carefully.

Regulations & Licenses

A valid Washington fishing license is required to fish Potholes Reservoir, and licenses can be purchased through the state's fish and wildlife agency. Regulations on this water can include species-specific size limits, daily bag limits, and seasonal rules, and these are subject to change from year to year. Some species may carry slot or minimum-size restrictions, and there can be special rules in particular areas or seasons. Before fishing, review the current Washington Department of Fish and Wildlife regulations for this reservoir and confirm bag and size limits, any gear restrictions, and open seasons so you stay compliant.

Frequently Asked Questions

What fish is Potholes Reservoir best known for?
Potholes is best known as a top walleye fishery and for quality largemouth and smallmouth bass. It also produces excellent crappie, yellow perch, bluegill, and a stocked rainbow trout fishery, making it one of the most diverse mixed-bag reservoirs in Washington.

When is the best time to fish Potholes Reservoir?
Spring and fall are prime. Spring brings shallow, catchable walleye plus spawning bass, crappie, and perch in the brushy north end, while fall's cooling water triggers heavy feeding across all species. Summer fishes well at dawn and dusk, and winter favors trout and panfish.

What are the 'sand dunes' at Potholes and why fish them?
The dunes are a maze of sandy islands, flooded brush, and channels in the north end of the reservoir. The cover and shallow structure make it classic habitat for largemouth bass, crappie, and panfish. It is best explored by boat, and navigation requires care because of shallow water and changing levels.

Do I need a license to fish Potholes Reservoir?
Yes. A valid Washington fishing license is required, available through the state fish and wildlife agency. Size limits, daily bag limits, and seasonal rules apply and vary by species and over time, so check the current Washington regulations for this reservoir before your trip.