I am sorry that i have not been able to post for a while due to computer problems and a heavy work load.
Lithuania is Latvia's neighbor to the south and speaks a distinct, albeit related language. Lithuania ruled a large area after the decay of the Mongol Empire in the area, including all of Belarus and a good portion of Ukraine. The royal line intermarried with the kings of Poland, and around 1400, the Lithuanian king also became king of Poland. This had the result of Lithuania becoming subordinate to Poland, and the Lithuanian gentry becoming Polonized. This has happened several times in history. Scotland became subject to England when King James of Scotland took over the throne of England as the closest heir of the royal line. Manchuria conquered China, and became assimilated by the Chinese. During the partition of Poland, Lithuania became part of the Russian Empire, except for the westernmost region which was part of the Prussian Empire [which was really German, the Prussians having been assimilated by the Germans by the beginning of the 18th cent.]
Like the Ukrainians and the other Baltic States, the Lithuanians attempted to establish an independent state during the final part of WWI. Like Latvia and Estonia, and unlike Ukraine, the Lithuanians succeeded. They were annexed by the Soviet Union in 1940, and only regained their independence in 1991. For further detail see this article.
Culturally, Lithuania is divided into between 4 and 7 regions, depending on which source you consult.The simplest categorization is to divide the country with more or less straight lines east-west and north-south which intersect a little to the northwest of the city of Kaunas. The northwest quadrant is called Samogitia, Žemaitija, or Lower Lithuania, the northeast is called Aukštaitija or Upper Lithuania, the southeast is called Dzūkija or Dainava, the land of song, and the southwest quadrant is called Suvalkija or Sūduva. Here is a map showing this.
Most sources would include a fifth region, Lithuania Minor, Mažoji Lietuva, or Klaipeda, after its largest city. The reason that some authorities do not include it is because most of the territory of Lithuania Minor is outside the present day borders of the state of Lithuania except for a narrow strip along the coast as you can see above. Here is a map of the five regions.
Here is a link to a local Lithuanian dance group website. You can see the variety of patterns and colors within the basic costume structure.