Keystone does not hold its layers the way a lake should. What stratifies this water is not cold sinking under warm — it is as much salt as temperature. The Cimarron arrives loaded with mineral runoff off the western plains, meets the Arkansas at the confluence, and leaves a reservoir where salinity runs 0.45 to 4.03 parts per thousand, genuinely low-brackish conditions for a lake this far inland. By late summer the column evens out top to bottom the way August should — and the chemocline holds anyway. Downstream of that chemistry, Mannford brands itself the Striped Bass Capital of the World while summer die-offs, last documented in August 2021, remain an annual worry. The water reads stained, not blue-green, and visitors split on it: one calls it beautiful for boating, others call the same water cloudy and stagnant. Fair enough, for a reservoir gathering two prairie rivers across 74,506 square miles of drainage, twenty-three miles from Tulsa.
curator · lake-level · as of Sep 3, 2026
The facts
- Surface area 52.6 km² usgs-3dhp · lake-level · as of Jun 2, 2026
- Nearest town Rigsby · 1.9 km osm-overpass · lake-level · as of Jun 2, 2026
- Bird species (within 25 mi) 216 ebird-api-v2 · lake-level · as of Jun 2, 2026
- Bird diversity index 0.9 ebird-api-v2 · lake-level · as of Jun 2, 2026
- Median home value $155,925 census-acs-2024-b25077 · block-group-level · as of Jun 2, 2026
- Water clarity Moderate curator · lake-level · as of Sep 3, 2026
- Night sky Dark skies viirs-black-marble-vnp46a4 · lake-level · as of Sep 3, 2026
- Surroundings Near-metro — a city within easy reach curator · lake-level · as of Sep 3, 2026
- Water origin Reservoir curator · lake-level · as of Sep 3, 2026
In more detail
- Climate
- strongly four-season; cool winters (~41°F mean), hot summers (~80°F); ~42 in precip/yr noaa-normals-1991-2020-descriptor · lake-level · as of Jun 2, 2026
- Public access
- Keystone Lake is a USACE (Tulsa District) reservoir co-managed with Oklahoma State Parks (Keystone State Park), with about 296.5 miles of shoreline and, per third-party aggregation, 11 boat ramps across 16 recreation areas. Public access includes courtesy docks, ADA-accessible berms near the tailwater/spillway, and Keystone State Park's Pier 51 Marina. Non-overnight visitors generally need a day-use pass at USACE-managed ramps/areas. Fees/permits: Non-overnight visitors must purchase a day-use pass at USACE-managed areas (e.g. Recreation.gov Day Use Passes 'Walnut Creek' and 'Appalachia Bay'); Keystone Ramp requires a day-use pass for boat-launch access.. Sources: wildlifedepartment.com (fetched 2026-07-12); omniafishing.com (search-extraction 2026-07-12); recreation.gov (search-extraction 2026-07-12); travelok.com (search-extraction 2026-07-12). curated-web-harvest · lake-level · as of Jul 12, 2026
- Dogs and pets
- high — 9 dog parks within 25 mi (OSM); state rule: Oklahoma law requires dogs to be leashed (or otherwise confined) to enter a state park or recreation area under the Oklahoma Tourism and Recreation Commission's jurisdiction; dogs running at large may be impounded, and vicious dogs posing an imminent threat may be destroyed by department employees. The statute does not itself specify a leash length, but multiple state-park visitor pages consistently cite a 10-foot maximum leash as the practical standard. (74 O.S. § 2217 (Public access and use of state parks — Prohibitions); the prior administrative pet rule, OAC 725:30-4-9, has been revoked, leaving the statute as the primary controlling provision as of this harvest., fetched 2026-07-12); Dogs must be leashed at beaches and trails at Keystone Lake and owners must pick up after them. (keystonelakeguide.com, search-extraction 2026-07-12) curated-web-harvest · lake-level · as of Jul 12, 2026
- Property tax
- 0.67% ACS effective-rate proxy (2024 ACS 5-year; Pawnee County anchor: $876 median real-estate taxes paid ÷ $131,500 median owner-occupied home value; Oklahoma proxy 0.80%, -0.13 percentage points). census-acs-2024-property-tax · county-level · as of Dec 31, 2024
Where it’s heading
Stable hand-rated for v0.1 · lake-level · as of Sep 3, 2026
Stable: a USACE flood-control/hydropower reservoir 23 miles from Tulsa with an established state-park, marina and campground shoreline (Mannford pop. 3,262; Pawnee County median home $155,925, 2024 ACS). The sheet documents no growth vector — no named permit or subdivision velocity — and no decline signal at place scale: the recurrent flood swings (+25 ft July 2019 with every ramp closed, +20 ft June 2025; USACE via DVIDS, News On 6) are operations on the weather's clock, not a trajectory, and the annual striped-bass die-off concern (ODWC 2022–23 survey) is a fishery condition, not a place decline.