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The 1 Best Swimming Holes in North Dakota

Every verified swimming hole in North Dakota, ranked from most to least visited by real review counts: 1 reservoir. Each entry covers the swim itself, the hike, parking, restrooms, and what you can bring on the water, and links to a full guide with photos, directions, fees, and safety notes.

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Every verified place to swim in North Dakota. Tap a marker to open its guide.

Table of contentsall 1 spots▾

1. Harmon Lake Swimming Beach

Mandan, North Dakotareservoir

Harmon Lake is a Morton County reservoir on Otter Creek about 8 miles north of Mandan, and the county has set it up as a proper multi-use park with a designated swimming area and sandy beach. For the Mandan area, this is a genuinely handy lake to swim in, with a boat ramp, kayak launch dock, and floating fishing pier all sharing the water.

The park runs on a summer schedule, with water service switched on around May 1 each year, so plan your visits for the warm months. There is no lifeguard or posted depth information, so keep an eye on kids around the deeper parts of the reservoir.

  • The water: A reservoir on Otter Creek with a designated swimming area and sandy beach, alongside a boat ramp, kayak launch, and floating fishing pier.
  • Getting in: No hike. The beach is part of the developed county park, with paved access off Highway 1806 and County Road 140.
  • Parking: Free. Fees are charged only for camping, 25 dollars a night for electrical sites and 15 for primitive, cash or check only.
  • Facilities: Three vault toilets on site in the recreation area.
  • On the water: Kayaks, canoes, paddleboards, and motorboats. Rentals from Paddle On, Tadpole Kayak Rental, and Dockside LLC.
  • Good to know: Sandy entry suits kids, but there is no lifeguard and no posted depth markers, so supervise closely around drop-offs.

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Planning a swimming hole trip in North Dakota

North Dakota has 1 verified natural places to swim in this guide: 1 reservoir. The most visited is Harmon Lake Swimming Beach near Mandan, with 9 reviews.

North Dakota swimming holes: FAQ

How many swimming holes are there in North Dakota?

We've verified 1 natural swimming spots in North Dakota, including 1 reservoir. Every listing was checked against USGS water data, public-land records, and first-hand accounts before being published.

Are these North Dakota swimming holes free?

Many are free, while some state parks and recreation areas charge a day-use fee. Each listing shows the fee we found in official sources, and where no fee was documented, we say so rather than guess.

When is the best time to swim in North Dakota?

Most spots are at their best from late spring through early fall, but conditions vary by site. Each listing includes the best-season note from our research plus a live weather link for planning your visit.

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