The buildings of Länsimäki were constructed on land bought from the Westerkulla estate, which has existed on the grounds since the 1630s.

[2] Another site of historical importance in Länsimäki is Myllymäki Park and its World War I-era fortifications.

[2][3] Länsimäki has both a primary and lower secondary school and several day care and kindergarten services.

The population of Länsimäki is 5,675 (1.1.2014), and its total area is about 3.1 square kilometres (1.2 sq mi), giving the district a population density of 1,800 inhabitants per square kilometre (4,700/sq mi).

This is due to the district being rigidly divided into densely constructed high-rise neighborhoods and largely unpopulated forest and farmland.