The Lithuanian territory is mainly flat, moved by slight hilly undulations to the SE (western offshoots of the Ošmjany heights), to the E (Pavištyciai hills, which reach the maximum altitude of 284 m) and to the W (Samogitian region, or “land Bassa ”), where Scandinavian Quaternary glaciers in their retreat phases deposited sands and clays. The main river is the Nemunas, which covers for 477 km the Lithuanian territory it enters from the S, first heading towards the N and then turning W after having wet the city of Kaunas: tributaries of the Nemunas are the Neris rivers (which also receives the waters of the Šventoji river), Nevežis, Dubysa and Šešupe. Other rivers of Lithuania are the Venta and the Muša, tributaries of the Baltic Sea. Numerous, but small, are the lakes (over 1300) of glacial origin. Lithuania also affects the northern part of the Kurski Zaliv (Courland lagoon), a vast stretch of sea separated from the Baltic Sea by a sandy cordon, into which the Nemunas flows into two main delta branches (Rusne to the N, Matrosovka to the S). The climate, transitional between the sub-Atlantic and the sub-continental one, is characterized by rigid and snowy winters and by cool and humid summers: in Kaunas the average annual temperature is 6.2 ° C, with values of -5 ° C in January and of 18 ° C in July. Precipitation is abundant,
According to iamhigher, the population of Lithuania is fairly evenly distributed on the territory, with an average density of 51 residents per km², and an annual growth coefficient of negative sign. Like the other former republics of the Soviet Union which have chosen complete independence and also renounced the forms of cooperation offered by the constitution of the Commonwealth of Independent States, Lithuania went through, after 1991, a phase of institutional, social and productive reorganization. However, in the case of Lithuania, those exoduses of the Russian population that characterized other republics of the USSR were lacking: the Lithuanian ethnic situation is much more stable than elsewhere, with a strong prevalence of Lithuanians (massive, in 1991, the return to the country after the dissolution of the USSR), a very scarce Russian presence and small communities of Poles, Belarusians, Ukrainians and Jews (which before the Nazi genocide constituted the largest minority). It should also be noted that the economic and infrastructural conditions were, at the time of independence, less precarious than most of the Soviet territory: the population has thus remained almost perfectly stable in terms of demographic movement, while also the inbound and outbound migratory flows have balanced out. The urbanization rate of the population is quite high (66.9%), which is concentrated mainly in the three main cities: the capital Vilnius which, located on the Neris River in the south-eastern region of the country, is an important economic and cultural center with a historic center rich in Gothic, Renaissance and Baroque architecture; Kaunas, a commercial and industrial center, located at the confluence of the Nemunas and Neris rivers; Klaipėda, an important fishing port overlooking the Baltic Sea and home to shipyards.
About a quarter of the Lithuanian territory is covered by forests consisting mainly of birch and alder in the central areas, of firs and pines in the northern and southern wooded areas. The forests are populated by elk, deer, wolves, lynxes, foxes and wild boars, while the otter and beaver live in inland waters. Also noteworthy is the notable presence of birds, including storks, herons and geese. The activity of Lithuanian industrial centers, as well as an unregulated use of drainage systems in rural areas, have brought the problem of air and water pollution to the fore. The main concerns mainly concern some cities, such as Vilnius, Kaunas, Jonava, Akmenė, Elektrėnai and Mažeikiai, home to chemical industries, refineries, cement factories and plants for the production of fertilizers, but the two Ignalina nuclear reactors, built on the model of the reactor that exploded in Chernobyl, also cause fears for environmental safety. No less serious is the problem of water contamination due not only to industrial discharges but also to the inefficiency of sewage disposal systems in urban areas. As a Soviet republic, Lithuania was the first to raise the problem and introduce environmental regulations but the lack of attention of the Moscow government (more interested in an increase in industrial production), as well as the backwardness and inefficiency of technologies, have not allowed to seriously address the issue of environmental protection. Since the early nineties of the last century, the Lithuanian government has undertaken a more incisive action by signing various international agreements on climate protection, disposal of harmful waste, protection of the ozone layer, elimination of discharges into the sea and conservation of wetlands. Numerous nature reserves and various regional and national parks have also been established, for a total of 6.1% of protected areas. Among the most important, the Kursiu Nerija National Park which preserves a unique lake and marine territory rich in pine forests, lagoons, beaches and sea coasts; Aukstaitija National Park, the first national park established in Lithuania (in 1974) which protects the environment and the ancient pine forests in the Ignalina, Utena and Svencionys region; the Žemaitija National Park in the northwest of the country and the Trakai National Park.