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Light Pollution Map USA - Dark Sky Parks and Bortle Scale Guide

See how bright the night sky is at your location on an interactive US light pollution map, color-coded from the darkest skies to the brightest inner-city skies using 2024 satellite data. The colors are light pollution zones, not Bortle classes, so we don't print a Bortle number - see why below. Enter a ZIP code or click anywhere on the map to check light pollution in your area, with the nearest certified dark sky parks ranked by distance and tonight's moon phase.

By Dan Rossall · Updated October 2026

How to Use the US Light Pollution Map

The light pollution map shows how bright the night sky is across the United States. It uses David Lorenz's 2024 atlas, modelled from VIIRS satellite night lights, color-coded by sky brightness from the darkest skies to the brightest inner-city skies. Enter a ZIP code, type a city name, or click anywhere on the map to check light pollution in that area and find the nearest dark sky sites ranked by distance. Use the toggle and opacity slider to show, hide or fade the layer.

Unlike static light pollution maps, this tool also shows over 100 certified International Dark Sky Places plotted on the map so you can find stargazing locations near you. The moon phase widget tells you whether tonight is good for stargazing, and you can share your location with a direct link.

The Bortle Scale, and Why the Map's Colors Aren't Bortle Classes

The map's colors are David Lorenz's light pollution zones, 0 to 7b. Each zone says how much artificial light adds to the sky straight overhead, compared with a natural dark sky. They are not measurements. In Lorenz's words, the maps are "a simulation of the artificial brightness at zenith (straight up)," made from VIIRS satellite night lights processed by the Earth Observation Group, Colorado School of Mines.

The Bortle Dark-Sky Scale, published by John Bortle in Sky & Telescope in 2001, rates a sky from 1 (pristine) to 9 (inner city) by what you can see. Lorenz describes it as "a subjective metric (gauged using your eyes) which takes into account the entire sky from horizon to zenith." Light domes from towns on the horizon count.

That is why a zone is not a Bortle class. Lorenz checked 397 nights of National Park Service observations and concluded that "zenith brightness and Bortle scale are too different to equate." The usual color pairings are off: "the yellow zone is usually taken to mean Bortle 4, however, yellow is more often in Bortle 5." He asks sites that use his maps not to "conflate the Bortle Scale with my maps." (Lorenz: Zenith Brightness vs Bortle Scale)

Bortle is still useful for judging a sky you're standing under. As a rough guide, you need Bortle 4 or darker to see the Milky Way clearly. Use the map to find a darker zone, then judge the Bortle class by eye when you get there.

Best Dark Sky Parks in the USA

The United States has more IDA-certified International Dark Sky Places than any other country, with over 100 parks, sanctuaries, reserves, and communities recognized for their commitment to protecting dark skies.

Natural Bridges NM, Utah

The world's first International Dark Sky Park (2007), with pristine skies in remote southeastern Utah.

Cherry Springs SP, Pennsylvania

One of the best stargazing sites east of the Mississippi, with a dedicated dark sky viewing area.

Big Bend NP, Texas

Remote Chihuahuan Desert park with some of the darkest measured skies in North America.

Great Basin NP, Nevada

Pristine skies above ancient bristlecone pines, with ranger-led astronomy programs.

Bryce Canyon NP, Utah

Famous hoodoo formations under dark skies, home to an annual astronomy festival.

Death Valley NP, California

The lowest and driest point in North America, with wide-open desert skies.

Stargazing Near Me - How to Plan a Trip

You do not need expensive equipment or a long drive to enjoy the night sky. Use our dark sky map to find stargazing spots near you, then follow these tips.

  • Check the moon phase -the darkest skies occur around a new moon. Even a half moon can wash out fainter stars and the Milky Way.
  • Let your eyes adapt -it takes 20 to 30 minutes for your eyes to fully adjust to the dark. Avoid looking at your phone screen (or use a red filter).
  • Check the weather -clear skies are essential. Cloud cover is the biggest obstacle to stargazing.
  • Dress warmly -you will be standing still in the dark, often in exposed locations. Temperatures drop significantly at night, even in the desert.
  • Start with binoculars -a pair of 10x50 binoculars will show you craters on the Moon, Jupiter's moons, star clusters, and more.
  • Use a star chart app -apps like Stellarium or Sky Guide can help you identify constellations and planets in real time.

Dark Sky Place Categories

DarkSky International (formerly the International Dark-Sky Association) certifies dark sky locations in several categories, all of which are shown on our map.

  • Dark Sky Parks -publicly or privately owned spaces with exceptional stargazing and quality outdoor lighting. Includes national parks, state parks, and other protected areas.
  • Dark Sky Sanctuaries -the most remote and pristine dark sky locations, often far from any artificial light. These include Cosmic Campground in New Mexico and the Oregon Outback.
  • Dark Sky Reserves -large areas with a dark core surrounded by communities that have adopted lighting policies to protect the night sky. The Central Idaho Dark Sky Reserve was the first in the US.
  • Dark Sky Communities -cities and towns that have adopted quality outdoor lighting ordinances. Flagstaff, Arizona became the world's first dark sky community in 2001.

Frequently Asked Questions

Where are the best places to stargaze in the US?

The best stargazing is at IDA-certified dark sky parks, particularly in the western states. Utah alone has over 20 certified locations. Other top states include Arizona, New Mexico, Colorado, and Texas. Enter your ZIP code to find the nearest dark sky site.

How do I check light pollution in my area?

Enter your ZIP code or a place name, or click your location on the map, and the tool gives the light pollution zone at that point: how much artificial light adds to the sky straight overhead, an estimate from David Lorenz's 2024 atlas of satellite data rather than a measurement. The overlay shows the same zones across the US, color-coded from darkest to brightest. Areas shown in black or dark grey have the least light pollution. The tool also lists the nearest certified dark sky parks and sites, ranked by distance from your location.

What is the Bortle scale?

The Bortle scale rates night sky darkness by eye, from 1 (darkest possible) to 9 (inner-city). In John Bortle's own descriptions, suburban skies are class 5 to 6 and city skies class 8 to 9. You need Bortle 4 or darker to see the Milky Way. Great Basin National Park in Nevada and the Cosmic Campground in New Mexico are rated Bortle 1 to 2 in their own applications to DarkSky International.

Is this a Bortle scale map?

No. The map's colors are David Lorenz's light pollution zones (0 to 7b), which show sky brightness straight up (zenith brightness), modelled from satellite data, while the Bortle scale is a subjective, whole-sky assessment made by an observer on the ground, light domes on the horizon included. Lorenz compared the two directly using 397 nights of real observations from the US National Park Service's Night Sky Team and recommends not treating them as the same thing. The color people usually pair with a Bortle class tends to be too optimistic: yellow is more often Bortle 5 than 4, and orange more often Bortle 6 than 5. That's why we show the light pollution zone rather than printing a Bortle number for your location.

Can you see the Milky Way from the US?

Yes, but you need low light pollution -ideally Bortle 4 or darker. On a clear, moonless night at a certified dark sky park, the Milky Way is clearly visible. The best months are April to September when the galactic center is above the horizon. Use the map to find darker zones and nearby dark sky parks.

When is the best time to go stargazing?

The best conditions are on clear, moonless nights. New moon periods give the darkest skies -check our moon phase widget. The Milky Way core is best seen April to September. Major meteor showers like the Perseids (August) and Geminids (December) are spectacular from dark sky parks.

Do I need a telescope for stargazing?

No. The naked eye is all you need to see constellations, bright planets, meteor showers, the Milky Way, and occasional aurora. A pair of 10x50 binoculars reveals craters on the Moon, Jupiter's moons, the Andromeda galaxy, and many star clusters. A telescope adds more detail but is not necessary to enjoy the night sky.

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