Harmon Lake Swimming Beach
Mandan, North Dakota
Verified · 3 independent sources
- WATER
- reservoir
- ACCESS
- Designated swim area
- FEE
- $25 per night
- SEASON
- Best in summer
About Harmon Lake Swimming Beach
Harmon Lake Swimming Beach is a designated sandy swimming hole at Harmon Lake Recreation Area, a Morton County-managed reservoir on Otter Creek (a Missouri River tributary) about 8 miles north of Mandan, North Dakota. The county park page explicitly lists a 'swimming area with sandy beach' among the site's amenities alongside camping, boating, and fishing facilities, making this a handy lake to swim in for the Mandan area.
The recreation area sits on the west side of Highway 1806 near the small community of Harmon, on a reservoir impounded from Otter Creek in the Missouri River floodplain of Morton County, North Dakota. It is developed as a multi-use county park with camping loops, picnic shelters, and a boat ramp surrounding the impoundment.
Swimming at Harmon Lake Swimming Beach
The official park page lists a 'swimming area with sandy beach' as one of the water-recreation features at Harmon Lake, alongside a public boat ramp with dock, a kayak launch dock, and a floating fishing pier. No first-hand swimmer accounts describing water clarity, depth, or bottom conditions were found.
How to get to this swimming hole
Located approximately 8 miles north of Mandan, ND, at the intersection of Highway 1806 and County Road 140, with paved access to the park.
The hike in
No hike is needed to reach the swimming beach: it's a drive-up, paved-access county park beach reached directly from the Highway 1806/County Road 140 park entrance. Separately, the park also has a 19.2-mile mountain biking and hiking trail network on-site for recreation, but this trail is not on the way to and is not required to reach the swim beach.
Walk from the parking area to the sandy beach is short (typical of a developed day-use lake beach); exact distance/time from lot to shoreline was not stated in any source found.
Plan your visit
Bringing kids
OK with supervision
Official park page confirms a designated 'swimming area with sandy beach' (gentle sand entry, generally favorable for kids), but no lifeguard presence, posted depth markers, or water-clarity/drop-off information could be found in any source checked, so caution around unsupervised depth changes in the reservoir is warranted.
Parking
Free
Paved access to the park from Highway 1806 and County Road 140. The official park page and fee schedule list charges only for camping ($25/night electrical, $15/night primitive, cash/check only); no separate day-use or beach parking fee was found in any source checked.
Restrooms
Yes
3 vault toilets on-site at Harmon Lake Recreation Area, per the official Morton County Parks page (not confirmed whether located directly at the beach vs. elsewhere in the park loop).
Hours
No posted daily operating hours were found. The Morton County Parks system's seasonal note says water service is turned on at Harmon Lake by about May 1 each year, indicating the park opens for the season around then and presumably closes for winter.
On the water
Official park page confirms a public boat ramp with dock, a dedicated kayak launching dock, and a floating fishing pier, indicating both motorized boating and paddle craft are accommodated. No wake zones, horsepower limits, or seasonal watercraft restrictions were stated in any source found. Two rental outfitters (Paddle On and Tadpole Kayak Rental) are listed with addresses matching the Harmon Lake park entrance itself (Hwy 1806 & Co. Rd 140 / 3244 Harmon Lake Rd), suggesting seasonal on-site or adjacent rental service.
Rentals nearby
Kayak and stand-up paddleboard (SUP) rentals; described as a local Bismarck/Mandan business renting and selling SUPs and kayaks
Listed address: Harmon Lake, Highway 1806 & County Road 140, Mandan, ND 58554 (i.e., at the Harmon Lake park entrance); phone 701-663-5580
Kayak rentals
Listed address: 3244 Harmon Lake Road, Mandan, ND 58554 (same address as the Harmon Lake Recreation Area itself); phone 701-301-2995
Pontoon, kayak, and paddleboard rentals (per business directory description: ~2 pontoons, 6 kayaks, 10 paddleboards in inventory)
4010 Southbay Drive SE, Bismarck, ND (roughly 15 miles from Harmon Lake, on the Missouri River side of the metro, likely serves Missouri River/Lake Oahe access rather than Harmon Lake specifically); phone 701-354-7321
Backstory
The nearby community of Harmon was platted in 1913, named for brothers George and H.H. Harmon. Harmon Lake itself is a reservoir built on Otter Creek, a tributary of the Missouri River, per Morton County government information cited by Wikipedia.
Harmon Lake Swimming Beach: FAQ
Does Harmon Lake Swimming Beach charge a fee?
No separate day-use/swimming fee was found. Camping fees at Harmon Lake are $25 per night for electrical sites and $15 per night for primitive camping; fees must be paid by cash or check (no credit/debit cards accepted).
Is Harmon Lake Swimming Beach kid friendly?
Official park page confirms a designated 'swimming area with sandy beach' (gentle sand entry, generally favorable for kids), but no lifeguard presence, posted depth markers, or water-clarity/drop-off information could be found in any source checked, so caution around unsupervised depth changes in the reservoir is warranted.
Do I need to hike to reach Harmon Lake Swimming Beach?
No significant hike is required. The swimming area is close to parking and access.
Where do I park for Harmon Lake Swimming Beach?
Paved access to the park from Highway 1806 and County Road 140. The official park page and fee schedule list charges only for camping ($25/night electrical, $15/night primitive, cash/check only); no separate day-use or beach parking fee was found in any source checked.
Can I bring a kayak or paddleboard to Harmon Lake Swimming Beach?
Official park page confirms a public boat ramp with dock, a dedicated kayak launching dock, and a floating fishing pier, indicating both motorized boating and paddle craft are accommodated. No wake zones, horsepower limits, or seasonal watercraft restrictions were stated in any source found. Two rental outfitters (Paddle On and Tadpole Kayak Rental) are listed with addresses matching the Harmon Lake park entrance itself (Hwy 1806 & Co. Rd 140 / 3244 Harmon Lake Rd), suggesting seasonal on-site or adjacent rental service.
When is the best time to visit Harmon Lake Swimming Beach?
Summer; the county park system reports turning water service on at Harmon Lake by around May 1 each year, indicating a seasonal opening tied to warmer months.
What are the rules at Harmon Lake Swimming Beach?
Camping is limited to 14 days within any rolling 30-day period across Morton County Parks. ATVs and side-by-sides require valid, street-legal registration and licensed drivers. Individual campsites are first-come, first-served; group campsites and shelters require reservations. Full written park rules exist as linked PDF documents (Morton County Park Rules and Regulations; Individual Rules) that were not directly retrievable.
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