It has around 99 kilometres (61.5 mi) of sandy coastline, of which only about 38 kilometres (24 mi) face the open Baltic Sea and which is the shortest among the Baltic Sea countries; the rest of the coast is sheltered by the Curonian sand peninsula. Lithuania's major warm-water port, Klaipėda, lies at the narrow mouth of the Curonian Lagoon (Lithuanian: Kuršių marios), a shallow lagoon extending south to Kaliningrad. The main river, the Nemunas River, and some of its tributaries carry international shipping.
The Lithuanian landscape has been smoothed by glaciers. The highest areas are the moraines in the western uplands and eastern highlands, with the maximum elevation being Aukštojas Hill at 294 metres (965 ft). The terrain features numerous lakes, Lake Vištytis for example, and wetlands; a mixed forest zone covers nearly 33% of the country. The climate lies between maritime and continental, with wet, moderate winters and summers. According to one geographical computation method, Lithuania's capital, Vilnius, lies only a few kilometres south of the geographical centre of Europe.
Phytogeographically, Lithuania is shared between the Central European and Eastern European provinces of the Circumboreal Region within the Boreal Kingdom. According to the World Wide Fund for Nature, the territory of Lithuania can be subdivided into two ecoregions: the Central European mixed forests and Sarmatic mixed forests.