Upper Potomac River Fishing: Smallmouth, Walleye, Flatheads

The non-tidal Potomac River forms Maryland’s southern boundary for over 200 miles, from Cumberland toward Washington, D.C., and DNR calls it Maryland’s most popular freshwater fishing destination. This guide covers what DNR says lives there, the walleye slot, the invasive flathead catfish and snakehead rules, the winter life-jacket law and how the river’s license reciprocity works. We use DNR’s Upper Potomac page and the 2026 Maryland Guide to Fishing and Crabbing.

The river and its fish

DNR describes a river with only two small hydro dams on the mainstem, Dams 4 and 5, with western sections that are cooler and have gravel, boulder, cobble and bedrock bottoms, and lower reaches with pools, glides and extensive submerged vegetation. The species it manages are smallmouth bass, largemouth bass, walleye, muskellunge and channel catfish.

Smallmouth bass. The smallmouth was first introduced to the river in 1854 and is the headline fish. DNR reports that reproduction has declined over the past decade, which it believes is due in large part to high flows in May and June, and that a supplemental stocking project began in 2019. We could not confirm that stocking is continuing. Survey results show that quality and preferred-size fish have increased over time and are well above the agency’s benchmark.

Walleye. Walleye were introduced through stockings that began in 1979 and are now distributed throughout the river, with the highest densities from Dam 5 downstream to Point of Rocks. DNR says they stay active through winter. For the slot rule, see below.

Muskellunge. DNR describes muskie as a relatively new addition to the river and links a state muskie program. We did not find size or limit figures on that page, so see the statewide non-tidal rule in the rules snapshot.

Channel catfish. DNR reports 40 to 60 channel catfish per electrofishing hour, with about three quarters of the population between 12 and 20 inches, and a population that has been fairly stable.

The walleye slot

From January 1 to April 15 the maximum harvestable walleye size is 20 inches, a 15 to 20 inch slot. The rest of the year the minimum is 15 inches. The daily limit is 5. Check the rules snapshot for the dates we verified.

Flathead catfish and snakehead

Flathead catfish are an invasive species that DNR first collected in 2012 and now finds from Dam 5 downstream to the District of Columbia. DNR documents a three-fold increase in relative abundance from 2016 to 2021 and a shift to larger fish, and says they can exceed 40 pounds. DNR asks anglers to remove and kill blue and flathead catfish rather than release them. There is no minimum size or creel limit, and it is illegal to release a live catfish into a different waterbody, with fines of up to $2,500 per fish. Northern snakehead (Chesapeake channa) also have no season or limit, and possessing one alive is illegal. Report illegal transport to the Natural Resources Police at 800-628-9944.

License and shared waters

Maryland’s non-tidal license covers the Maryland side. The guide’s reciprocal-license rules let West Virginia residents with a West Virginia license fish the Potomac mainstem opposite their shore, and let a Maryland resident with a non-tidal license fish the West Virginia and Virginia banks opposite Maryland. Reciprocity runs from waters’ edge to waters’ edge and does not include tributaries or fishing from shore.

Access and boating

The C&O Canal National Historical Park parallels the river for 184.5 miles, with public access along the Maryland shoreline, and DNR lists many public boat ramps. The shallow, rocky river suits jet-drive boats or paddle craft. Water above the dams suits larger boats.

Tackle that suits it

A medium-light to medium spinning rod around 6 and a half to 7 feet with 6 to 10 pound line is the usual choice for smallmouth on tubes, jerkbaits and topwater. For walleye, jigs and minnows on a medium rod work. For flatheads, a heavy rod with strong line and cut bait suits the job. These are typical choices, not requirements.

What we could not confirm

DNR’s page still says supplemental smallmouth stocking would continue “through 2024,” and we did not find a newer statement. We also did not read current flow data, so use the hotlines and USGS sources in the rules snapshot. We are not describing access points by name beyond DNR’s general statements.

Related guides

See the walleye guide and the snakehead guide for statewide rules.