A dark-sky preserve (DSP) is an area, often near a park or observatory, that limits or decreases light pollution or keeps the night sky naturally dark and protected. Different groups have used various names for these areas because they created programs independently. DarkSky International (DarkSky) uses terms like "International Dark Sky Reserve" (IDSR) and "International Dark Sky Park" (IDSP) when certifying places as dark sky areas.

History

DarkSky International was created in 1988 to protect land for viewing the night sky and stars. Dark-sky preserves are protected because they are important for culture, science, nature, education, and people's enjoyment.

In 2007, the Mont Mégantic Observatory in Quebec became the first place to be officially recognized as an International Dark Sky Reserve. That same year, Natural Bridges National Monument in Utah became the first International Dark Sky Park. In 2015, the Gabriela Mistral Dark Sky Sanctuary in the Elqui Valley of Chile was named the world's first International Dark Sky Sanctuary.

A dark-sky preserve or reserve must be dark enough to help people study the stars. The rules for lighting in these areas are based on how animals are affected by artificial light at night.

Canada has strict rules for dark-sky preserves. These rules cover lighting within the preserves and how light from cities nearby affects the sky. These rules were developed with help from the Royal Astronomical Society of Canada.

Dark Sky Places

DarkSky International's Dark Sky Places program currently has five types of designations:

• International Dark Sky Communities – These are officially organized cities and towns that create rules for outdoor lighting and work to teach residents about the importance of protecting dark skies.
• International Dark Sky Parks – These are public or private areas protected for nature that use good outdoor lighting and offer programs to help visitors learn about dark skies.
• International Dark Sky Reserves – These areas have a central "core" zone that is very dark, surrounded by areas where people live. Rules are put in place to keep the core dark, and these sites are managed by groups of landowners working together.
• International Dark Sky Sanctuaries – These are the most remote and darkest places in the world. Because they are far from people, it is hard to reach them, so this designation helps raise awareness and protect these areas long-term.
• Urban Night Sky Places – These are not part of other categories but are recognized for teaching the public about the benefits of outdoor lighting that keeps people safe while protecting the natural nighttime environment. These places are often parks or open spaces near cities, designed to provide a real nighttime experience despite artificial lights.

The Dark Sky Developments of Distinction designation was given to neighborhoods or communities that promote natural night skies but did not qualify for the International Dark Sky Community program. This designation was no longer used after 2020.

Other designations include "Dark Sky Nation", given to the Kaibab Indian Reservation, and "Parashant International Night Sky Province—Window to the Cosmos", given to Grand Canyon-Parashant National Monument.

Dark sky preserves, reserves, and parks

As of January 2023, there are 201 officially recognized Dark Sky Places around the world: 38 Communities, 115 Parks, 20 Reserves, 16 Sanctuaries, 6 Developments of Distinction, and 6 Urban Night Sky Places.

Protected zones

Some areas are protected without mentioning an observatory or a park. These include:

• Areas in Coquimbo, Atacama, and Antofagasta in northern Chile
• The island of La Palma in the Canary Islands
• The Big Island of Hawaii
• Beach areas in Florida limit bright lights to help baby sea turtles survive.

By country

In the Canadian program, lighting in protected areas must be carefully controlled to reduce harm to wildlife. These rules are stricter than in other countries because Canada has large natural areas that need special protection. Canadian dark-sky preserves (DSPs) work with visitors to the site and also help improve lighting rules in nearby cities. Currently, dark-sky preserves have more authority to manage both inside and outside lighting than other similar programs.

As light pollution increases in some areas, observatories have partnered with nearby cities to create zones where lighting is carefully managed. These zones may not yet be officially named dark-sky preserves.

Although dark-sky preserve status is often requested by astronomers, protecting natural darkness helps wildlife that is active at night. For example, black-footed ferrets were reintroduced to Grasslands National Park, a dark-sky preserve. The success of this effort is supported by the dark skies maintained through the DSP agreement.

The island of Rùm in the Hebrides became a Dark Sky Sanctuary in 2024. The island’s small population values the dark sky and understands that too much artificial light harms young Manx Shearwater birds that nest there. The local community worked to achieve this status. This is the second Dark Sky Sanctuary in Europe and the first in Scotland.