The aim of this study has been to describe the ongoing region enlargement process in the region Mälardalen, located in the east part of Sweden, and to investigate how this process can affect the local level. The study is especially orientated on public communications and accessibility. The intention has also been to examine how the local accessibility can affect the re-gional development in Mälardalen. The local investigation object that has been chosen for this research is the city Strängnäs, situated in the province of Södermanland. The city of Strängnäs and the cities in it?s near geographic surroundings has been the benchmark for this Casestudy, in which the local accessibility with public transportation has been investigated.