Mülheim an der Ruhr, also called "City on the River", is a city in North Rhine-Westphalia in Germany. It is located in the Ruhr Area between Duisburg, Essen, Oberhausen and Ratingen. It is home of many companies, especially in the food industry, such as the Aldi Süd Company or the Tengelmann Group.

Mülheim received its town charter in 1808, and 100 years later the population exceeded 100,000, making Mülheim officially a city. At the time of the city's 200th anniversary with approximately 170,000 residents, the city was counted among the smaller cities of Germany.

Mülheim was the first city in the Ruhr Area to become totally free of coal mines, when its last coal mine "Rosenblumendelle" was closed. The former leather and coal city had successfully made a complete transformation to a diversified economic centre. With more than 50% covered by greenery and forest, the city is regarded as an attractive place to live between Düsseldorf and the Ruhr. It is the home of two Max Planck Institutes and, since 2009, the technical college Ruhr West. It has a station on the important railway between Dortmund and Duisburg and is served by Rhine-Ruhr S-Bahn lines S1 and S3.