Pornainen (Finnish: [ˈpornɑi̯nen]; Swedish: Borgnäs) is a small municipality of Finland. It is located in the province of Southern Finland and is part of the Uusimaa region. The neighboring municipalities are Askola in the east, Mäntsälä in the north, Porvoo in the southeast and Sipoo in the southwest. It is located 18 kilometres (11 mi) east of the town of Järvenpää.
The municipality has a population of 4,959 (31 August 2024) and covers an area of 150.09 square kilometres (57.95 sq mi) of which 3.59 km2 (1.39 sq mi) is water. The administrative centre of municipality is Kirveskoski (about 2,000 residents), also known as Pornainen's church village, and second largest village is Halkia (about 500 residents). The population density is 33.84 inhabitants per square kilometre (87.6/sq mi).
Movies and scenes for TV productions and short films have been filmed in Pornainen from the 1930s to the present day. In the publications of film industry, Pornainen was once named the most photographed locality in Finland, that is why the municipality has marketed itself under the nickname "Hollywood of Finland". The village of Laukkoski is known as a summer destination for many former celebrities, such as actress Regina Linnanheimo, and writers Mika Waltari and Juhani Aho.
The municipality is unilingually Finnish.
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