The hilly relief of the ŽNP was formed by a glacier retreating about 10-12 thousand years ago. Round kame hills and moraine mountain ridges, surrounding the pit of Lake Plateliai, numerous deep or shallow lakes, swamps and winding streams are characteristic of the relief. The highest point – 191.8 m, the lowest one -110 m above sea level.
The whole territory of the park is a part of the Žemaitijos highlands that includes: hilly stretches of Plateliai and Plokštinė, Barstyčiai ridge, Plateliai scoop (formed by the Plateliai group of lakes).
Sod-podzolic, bog, sod-bog, sod-podzolic-gley soils are typical for the Park area. The annual rate of percipitation in the Park is approximately 1000 mm. 56% of percipitation evaporate in the territory of the Park, the rest gets into the rivers through the surface of the land.