Mäntsälä (Finnish pronunciation: [ˈmæntsælæ]) is a municipality in the province of Southern Finland, and is part of the Uusimaa region. It has a population of 20,782
(31 December 2020) 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
35.78 inhabitants per square kilometre (92.7/sq mi).