Jordanelle State Park
A big Provo River reservoir in the Heber Valley, certified 2021 — and honest that it is a Bortle 4.
Heber Valley · Wasatch Back · Provo River
State Park 6,700 acres 6,400 ft high point Est. 1995 Utah Division of State Parks Dark Sky Park
Overview
Jordanelle is a big reservoir on the Provo River in the Heber Valley, with Park City up the hill, Heber and Midway on the flat, and Deer Valley's lights above. It is a boating and camping park first, and a dark-sky park second — its own survey puts it at Bortle 4 and an SQM-L average of 21.00, which is the brightest of any certified Dark Sky Park in this corpus except Antelope Island. That is not a criticism; it is the point. Jordanelle's certification is an argument about access and stewardship in a valley that is growing fast, not a claim about pristine darkness. The park is candid, and the record follows suit.
Getting in
When to go
Best: Jun, Jul, Sep
A busy summer water park. Autumn is the best combination of dark, clear and quiet. Winter brings inversions and snow-reflected town light.
Safety & conditions
Activities
Stargazing
Certified 2021. Bortle 4, SQM-L 21.00 — the brightest certified Dark Sky Park in this corpus bar one, and the park does not pretend otherwise. Ranger star parties in season.
Season: Year-round; new-moon best. Avoid inversion and heavy-snow nights.
Camping
Large campgrounds at Hailstone, and quieter walk-in sites at Rock Cliff.
Regs: Reservable through Utah State Parks; it is busy.
Fishing
Trout, bass and perch on the reservoir; the Provo below the dam is a blue-ribbon fishery.
Cycling
The Jordanelle Perimeter Trail, and connections into the Park City network.
Hiking
Shoreline and perimeter trails; boardwalks through the wetland at Rock Cliff.
Night Sky
Dark Sky Park Certified 2021 Bortle 4 21.00 mag/arcsec² across 3 sites
Bortle 4 — and the lights are on three sides. Park City and Deer Valley above, Heber and Midway on the valley floor, and the Wasatch Front over the ridge. What moves the number: moon, snow cover reflecting town light back up, and winter inversions.
What the sky does here
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Typical
Bortle Class 4: The Contested Sky
Under a Class 4 sky, the Milky Way remains visible overhead, but obvious light domes occupy parts of the horizon. Wilderness and development are both present, and the emotional experience changes depending on which direction a person faces.
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Only when
Bortle Class 5: Wilderness with an Address
On a winter night with snow on the ground and an inversion overhead, with Park City and Deer Valley lit above the valley — snow reflects town light straight back into the sky.
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Only when
Bortle Class 3: Civilization Beyond the Rim
Out at Rock Cliff, on the far eastern arm of the reservoir, on a clear moonless night with the water and the delta between you and Heber.
Geology
Heber Valley basin fill and outwash, with the Wasatch rising steeply to the west.
Province: Wasatch Range — Middle Rocky Mountains
Rock types: limestone, sandstone, glacial outwash
Major formations
Also present: Twin Creek Limestone
Ecology
Biomes: sagebrush steppe; riparian along the Provo; wetland at the Rock Cliff delta
Flora
- sagebrush
- willow and cottonwood on the delta
Fauna
- moose
- mule deer
- osprey
- bald eagle
- sandhill crane at Rock Cliff
The Rock Cliff area protects the Provo River delta — a genuinely good wetland in a valley that is filling up with houses.
History
The Heber Valley is within the ancestral homeland of the Ute people, whose connection to this country continues today. Jordanelle Dam was completed in the early 1990s as part of the Central Utah Project, flooding the Provo River bottoms; the park opened in 1995.
Modern issues
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Heber Valley growth
Status: ongoing
Park City above, Heber and Midway alongside, and one of the fastest-growing valleys in the West filling in around the reservoir. Certification here is a line being held, not a victory.