In 1971 it was amalgamated with Kållered and Lindome (the latter transferred from Halland County).

The municipality has four main parts: Mölndal, Kållered, Lindome and Hällesåker.

This is a demographic table based on Mölndal Municipality's electoral districts in the 2022 Swedish general election sourced from SVT's election platform, in turn taken from SCB official statistics.

[2] In total there were 69,838 residents, including 51,607 Swedish citizens of voting age.

Indicators are in percentage points except population totals and income.