🇫🇮 Mäntsälä

Mäntsälä is a municipality in the province of Southern Finland, and is part of the Uusimaa region. It has a population of 20,861 (31 December 2025) and covers an area of 596.11 square kilometres (230.16 sq mi) of which 15.26 km2 (5.89 sq mi) is water. The population density is 35.91 inhabitants per square kilometre (93.0/sq mi). The municipality is unilingually Finnish. Mäntsälä is one of three municipalities in the Uusimaa region that do not have a Swedish name; the others are Nurmijärvi and Askola.