Länsimäki is located by the border of Helsinki in southwestern Vantaa. The area borders on Porvoonväylä road in the north, Ring Road III in the northeast and Itäväylä road in the east. Länsimäki is easily accessible by metro via the Mellunmäki station, which is only a ten-minute walk from Tykkikuja street.

For families with children there is a primary and lower secondary school as well as several day care centres in the area. The small shopping centre has a grocery store, restaurant and post office. There is also a youth hall, library and a Citizen Services One Stop Shop in Länsimäki. Located near the metro station, this new district now also has a church, social and health centre, drop-in centre and a grocery store.