The park encompasses most of the Archipelago Sea region east of Åland and south of the main islands of Korpo, Nagu, Pargas, and Kimitoön.

[4] The park is mainly situated in the (former) municipalities of Nagu, Korpo, Houtskär, Iniö, Hitis, and southern Pargas.

One of the objectives of the national park is to protect the archipelago's cultural landscape—such as the considerable areas used for traditional agriculture—in addition to the natural landscape.

The area also supported large populations of grey seals and seabirds, the latter of which were rich sources of eggs, meat, and down for early humans.

[6] During the Neolithic period and the Bronze Age, the archipelago's outermost islets were located around the present-day main islands of Nagu, Korpo, and Houtskär.

For example, the Neolithic settlement of Bötesberget in the municipality of Dragsfjärd, dated from 6000 BCE, would have originally been on an isolated island in the middle of open water.

[citation needed] The southwestern archipelago became a part of the northern Baltic Sea region cultures, which had common means of livelihood, use of metals, and burial customs.

[7] In the beginning of the Bronze Age, barrows were used to entomb dead bodies, sometimes with jewelry or weapons; later, cremation became customary.

Often, the burial sites were chosen so as to stand out from the surrounding landscape, such as on rocky hills with a view to the sea, or near (but not atop) the highest place on an island.

During the Iron Age, these areas would have bristled with islets, and were close to fishing and seal hunting grounds in the outer archipelago.

[7] In the late 13th century, Swedish settlers moved to the area from Svealand, southern Norrland, and Götaland, substantially increasing the population.

The population in the archipelago increased until the mid-16th century, after which it started to decline rapidly due to insufficient natural resources.

[5] In the mid-19th century, technical development in fishing methods (such as hook and drift nets) made it possible for people to live outside traditional villages, leading to fast population growth.

The shuttle ship harbours at Prostvik and Pärnäs in Nagu and Kasnäs in Kimitoön are accessible by road and have bus connections.

Building campfires is allowed only in designated places, unless mandated otherwise (i.e., fire-making is prohibited if a forest fire warning is in effect).