According to the CIA World Fact Book, the capital of Lithuania is Vilnius.
Capital of Lithuania:
Vilnius is the capital and largest city of Lithuania and is located in
"Wilno (Vilnius)is the capital of the present day Lithuania and one of
the country's oldest cities. It stretches along both banks of the fast
flowing Neris River, and is set among hills pine forests.
Wilno(Vilnius) is very old city. The honour for founding Wilno is
justly given to Gediminas (Lithuanian Duke) in 1323. Having declared
Wilno his "Royal Town", Gediminas created the conditions for its
subsequent growth as well as the political, economical and cultural
center of Lithuania."
"The capital of the Republic of Lithuania is VILNIUS. Naturally, it is
the largest city in the country: according to the data of 2001 the
population of Vilnius is 542.287. Of them 57.8% are Lithuanians, 18.7%
Poles, 14% Russians, 4% Byelorussians, 0.5% Jews and the remaining 5%
comprising some other nationalities."
Vilnius in Wikipedia
See alternative names of Vilnius here:
I hope this is helpful!