Dzūkija or Dainava is one of five ethnographic regions of Lithuania. Dzūkija is a cultural region defined by traditional lifestyles and dialects of the local Lithuanian population (mostly rural farmers) and has never been defined as a political or administrative unit. Traditionally, Alytus is regarded as the capital of the region, although it is not the largest city in Dzūkija.
Dzūkija is situated in southeastern Lithuania, and consists of Alytus County and southern Vilnius County. Historically, it extended into what is now northeastern Poland (Podlaskie Voivodeship) and northwestern Belarus (Grodno Region).
Large parts of Dzūkija have light sandy soil, unsuited for agriculture. Therefore, the region is densely covered with pine forests, one of which is Dainava Forest, the largest in Lithuania. The Čepkeliai Marsh, the largest swamp in Lithuania, is situated in the region, near the border with Belarus. Dzūkija is also the most sparsely populated region in Lithuania, with average population density dropping below 15 people per square kilometer in Varėna district municipality. Due to lower harvests in infertile soil, the region was relatively poorer than the rest of Lithuania. Farmers had to supplement their yields with edible mushrooms and berries collected in the forests. Mushroom hunting remains an important part of the local economy.
Two of the five national parks in Lithuania are to be found in Dzūkija: Dzūkija National Park east of Varėna (established there in 1991), and Trakai National Historic Park near Trakai (1992).