Helsinki is the capital and largest city in Finland. It is in the southern part of Finland, on the shore of the Gulf of Finland, by the Baltic Sea. The population of the city of Helsinki is 584,420 (31 March 2010), making it the most populous municipality in Finland by a wide margin. Helsinki is located some 400 kilometres (250 mi) east of Stockholm, Sweden, 300 kilometres (190 mi) west of St. Petersburg, Russia and 80 kilometres (50 mi) north of Tallinn, Estonia. Helsinki has close connections with these three cities.

The municipality of Helsinki forms the heart of the Helsinki metropolitan area and Greater Helsinki area. Over one million people live in the Helsinki metropolitan area, which includes the city of Helsinki and three other cities. Two of these cities, Espoo and Vantaa, immediately border Helsinki to the west and north. Kauniainen, the third city, is an enclave within the city of Espoo. The Helsinki metropolitan area is the northernmost urban area on Earth with a population of over 1 million people, and the city is the northernmost capital of an EU member state. Altogether 1.3 million people live in the Greater Helsinki area, which includes the aforementioned cities and 9 suburban satellite towns. Approximately 1 in 4 Finns live in the Greater Helsinki area.

Helsinki is Finland's major political, educational, financial, cultural and research center. Helsinki is also an important regional city on the Baltic Sea and northern Europe. Approximately 70% of foreign companies operating in Finland have settled in the Helsinki region.

Since early 2009, Helsinki has begun to contemplate a possible merger with Vantaa. On 30 March 2009, the city council of Vantaa agreed to review Helsinki's proposal of a possible merger. The city council emphasizes that the review is not about the possibility of ceasing the existence of the city of Vantaa.

In 2009, Helsinki was chosen to be the World Design Capital for 2012 by the International Council of Societies of Industrial Design. Helsinki narrowly beat Eindhoven for the title.