Cedar Breaks National Monument
A 2,000-foot-deep eroded amphitheatre at over 10,000 feet, certified in 2017 — one of the highest and darkest small units in the system.
Markagunt Plateau · Cedar Mountain
National Monument 6,155 acres 10,662 ft high point Est. 1933 National Park Service Dark Sky Park
Overview
Cedar Breaks is Bryce Canyon's high, cold, empty cousin. Same rock — the pink and orange Claron Formation — eroded into the same kind of amphitheatre, but here the rim sits above 10,000 feet on the Markagunt Plateau, the winters are deep enough to close the road, and almost nobody comes. Six thousand acres, a rim drive with four overlooks, and a bristlecone grove. The altitude is what makes the sky: less air above you, and the Milky Way visible horizon to horizon on a moonless night. The monument is also, in this project, the most methodologically honest document we found — it is the park that wrote down that the Milky Way itself brightens a sky-quality meter by up to three tenths of a magnitude when it passes overhead, which is a caution that applies to every number in this corpus.
Getting in
When to go
Best: Jul, Aug, Sep
The season is short. Snow closes the rim road roughly November to late May, and the wildflowers peak in July and August. That also means the monument is closed to cars during the longest, clearest, darkest nights of the year.
Safety & conditions
Activities
Hiking
Short rim trails — Spectra Point and the Ramparts Trail out along the edge, past bristlecones a thousand years old.
Season: Late June through October. The road is closed by snow the rest of the year.
Everything here is above 10,000 feet. It is not a hard hike; it is a hard hike at altitude.
Stargazing
Certified 2017. Star parties at Point Supreme through the short summer season, at 10,000 feet on a plateau rim — the altitude is doing most of the work. The park self-assesses as a Class 2 or 3 sky; the NPS never assigned it a number.
Season: Summer and early autumn — the road is closed in winter, which removes the darkest, clearest nights of the year from public access.
The light that hurts here sits on the horizon, to the west and north — and a zenith-pointed meter cannot see it. The park says so plainly.
Scenic Driving
A five-mile rim drive with four overlooks. That is the whole road.
Season: Late spring through autumn; closed by snow.
Camping
A small seasonal campground on the rim at 10,000 feet.
Winter Sports
The rim road becomes a snowmobile and ski route in winter; the monument stays open, the road does not.
Season: Winter.
Night Sky
Dark Sky Park Certified 2017 Bortle 2–3 measured 21.49 mag/arcsec² across 9 sites
No Bortle typical is recorded: the park self-assesses as 'a Class 2 or Class 3 sky' and the NPS never assigned it a class. The monument sits above 10,000 feet, which is most of why it is dark — less air overhead. What degrades it is on the horizon, not above: the application says 'degradation of the night sky at Cedar Breaks is predominantly due to light domes within about 20 degrees of the horizon to the west and north, WHICH ARE NOT CAPTURED BY THE SQM.' Cedar City and St. George make the brightest domes; Brian Head Town sits just off the northern boundary. Washington County, which holds St. George, grew ten per cent in four years and is among the fastest-growing in the country. What else moves it: moon, altitude haze, and the Milky Way itself.
What the sky does here
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Typical
Bortle Class 2: The Wilderness Has Its Own Light
Under a Class 2 sky, darkness is nearly natural yet the landscape remains emotionally legible. The Milky Way becomes architecture, still water can carry a second sky, and the night feels less alien than complete.
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Only when
Bortle Class 3: Civilization Beyond the Rim
At North View and the northern boundary, where the observers could see Brian Head Town's skyglow directly — and on any night when the Cedar City and St. George domes are sitting on the western horizon.
Across the park
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The northern boundary — North View, UT 143
21.46 mag/arcsec² 2 sites
The brightest ground in the monument, and the only sites where the observers could actually see a town. Brian Head sits immediately off the northern boundary. Measured at 21.13 on the same night — the park read the town itself as a comparison.
Light domes: Brian Head Town
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The rim overlooks — Point Supreme, Chessman Ridge, Sunset View
21.50 mag/arcsec² range 21.49–21.54 4 sites
Where the astronomy programmes happen and where almost everyone stands. Consistent across the rim — the park notes the sky is "quite consistent" across the monument.
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The western half of the monument
Never measured
NEVER MEASURED. The application is candid: "The western portion of the monument is about two miles closer to Cedar City, but is not accessible by road or trail so staff has not yet been able to take SQM measurements from this part of the monument." A comparison reading at Cedar Canyon Campground, southwest and outside the boundary, came back at 21.51 — comparable to the rest — which the park offers as evidence the west is probably not much brighter. Probably.
Geology
The same Claron Formation that makes the hoodoos at Bryce, eroded here into a single vast amphitheatre rather than a field of spires. Iron and manganese give the pinks, oranges and purples.
Province: Colorado Plateau — Markagunt Plateau, the Pink Cliffs
Rock types: limestone, siltstone
Major formations
Also present: Claron Formation
Ecology
Biomes: subalpine meadow; spruce-fir forest; bristlecone pine on the exposed rim
Flora
- Great Basin bristlecone pine on Spectra Point
- Engelmann spruce and subalpine fir
- summer wildflower meadows
Fauna
- mule deer
- marmot
- pika
- Clark's nutcracker
High, cold and short-seasoned. The wildflower display in July and August is the reason most daytime visitors come.
History
The Markagunt Plateau is part of the ancestral homeland of the Southern Paiute, whose relationship to this country continues. Proclaimed a national monument in 1933.
Modern issues
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Regional growth
Status: ongoing
The application flags Cedar City and St. George as the brightest domes and notes Washington County grew ten per cent in four years to 138,115 people, among the fastest growth in the United States. The monument is small and its horizon is not protected.
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The unmeasured half
Status: open
The western half of the monument, nearer Cedar City, has never been measured — no road, no trail.