Tallinn is the capital and most populous city of Estonia. Located on a bay in northern Estonia, on the shore of the Gulf of Finland of the Baltic Sea, it has a population of 460,584 as of 2026 and administratively lies in Harju County. As of 2024, the population of the Tallinn metropolitan area is estimated at 646,315. Tallinn is the main governmental, financial, industrial, and cultural centre of Estonia. It is located 187 kilometres (116 mi) northwest of the country's second largest city, Tartu, however, only 80 kilometres (50 mi) south of Helsinki, Finland. It is also 320 kilometres (200 mi) west of Saint Petersburg, Russia, 300 kilometres (190 mi) north of Riga, Latvia, and 380 kilometres (240 mi) east of Stockholm, Sweden. From the 13th century until the first half of the 20th century, Tallinn was known in most of the world by variants of its other historical name, Reval.
Summary from Wikipedia.