The National Marine Park of Alonnisos is the first to be founded in Greece. It is located in Eastern Central Greece, in the region of the North Sporades Islands. The Sporades administratively belong to the district of Skopelos in the Prefecture of Magnesia.

Alonissos is the largest island in the Park. The highest level of local government within the Park is the County Council of Alonnisos. The Park also encompasses six smaller islands (Peristera, Kyra Panagia, Gioura, Skantzoura, and Piperi) and 22 uninhabited islands and rocky outcrops.

FOUNDED: By Presidential Decree G.G. 519/92 on 28/5/92

AREA: Zone A (strict protection): 1587 Km² - Zone B (protected area): 678 Km²

COMMUNITIES: Restricted to Zone B. The largest of these are Patitiri, Palia Alonnisos, Votsi and Steni Vala

GEOLOGY: Limestone rock dominated the area. Its main characteristics are the steep rocky slopes which run down to the sea and the caves, which are an important part of the habitat of the monk seal. Different types of soil are encountered.

CLIMATE: Mediterranean, with a wet winter and dry summer. The average annual temperature is 17 C and the average rainfall is about 515mm

SPECIAL CONDITIONS: The geographic isolation of the area, its morphology, the limited degree of human interference and the excellent condition of the natural environment make the land and sea areas of the Park an ideal habitat for many threatened species of plants and animals.