How dark is the sky in Minnesota?
Sky darkness for 53 towns and parks in Minnesota, worked out from NASA satellite images of light at night (2025). 38 of them have skies of Bortle 4 or darker, where the Milky Way shows overhead. The darkest is Judge C. R. Magney State Park (21.88, Bortle 3), the brightest Minneapolis (17.20, Bortle 8).
19
Bortle class, 1 pristine to 9 city center
park or dark-sky place
city
Numbers like 21.95 or 16.97 are the brightness of the sky overhead on a clear, moonless night, in mag/arcsec². The scale runs backwards: a lower number means a brighter sky, from about 22 for a natural sky to about 17 in a city center.
How the readings are made
Darkest skies in Minnesota
- Judge C. R. Magney State ParkBortle 321.88
- Grand Portage State ForestBortle 321.86
- Superior National ForestBortle 321.86
- Voyageurs National ParkBortle 321.86
- Finland State ForestBortle 321.85
Among the places on this site. Plenty of land between them is just as dark, with no town or park to name it by.
Brightest city skies in Minnesota
All 53 places in Minnesota
Amber names are parks and certified dark-sky places. The figure is the Bortle class: 1 darkest, 9 city center.
Badoura State Forest4Banning State Park4Battleground State Forest3Bear Head Lake State Park3Beaver Creek Valley State Park4Big Bog State Recreation Area3Blaine8Bloomington8Blue Mounds State Park4Bowstring State Forest3Brooklyn Park8Burnsville8Chippewa National Forest4Cloquet Valley State Forest4Duluth7Eagan8Eden Prairie8Father Hennepin State Park4Finland State Forest3Fond du Lac State Forest4Forestville/Mystery Cave State Park4Frontenac State Park4Gooseberry Falls State Park4Grand Portage National Monument3Grand Portage State Forest3Grand Portage State Park4Great River Bluffs State Park4Itasca State Park4Jay Cooke State Park4John A. Latsch State Park4Judge C. R. Magney State Park3Kabetogama State Forest4Lake Bemidji State Park4Lake Shetek State Park4Lake Vermilion-Soudan Underground Mine State Park4Lakeville8Minneapolis8Paul Bunyan State Forest4Pipestone National Monument5Plymouth8Rice Lake State Park4Rochester8Saint Cloud8Saint Paul8Savanna State Forest4Solana State Forest4Split Rock Lighthouse State Park3St. Croix State Park4Superior National Forest3Temperance River State Park3Upper Sioux Agency State Park4Voyageurs National Park3Woodbury8