The district's seat (capital city) is Schwelm; the largest of its nine towns is Witten.

In 1970 and 1975 it was modified a bit during the reorganization of the districts in North Rhine-Westphalia; most notable was the inclusion of the previously independent city of Witten in 1975.

Since 2015, the district administrator of the Ennepe-Ruhr-Kreis has been Olaf Schade of the Social Democratic Party (SPD).

In the most recent election on 13 September 2020, Schade was re-elected with the support of the SPD and The Greens, winning 61.6% of votes against Oliver Flüshöh, who was nominated by the Christian Democratic Union (CDU) and Free Democratic Party (FDP).

In the middle of the coat of arms there is the checked red-white bar of the County of Mark, which owned the area in medieval times.