Pfaffenhofen an der Ilm is a municipality in Bavaria, Germany, capital of the district Pfaffenhofen. It is located on the river Ilm, and had a population of 23,282 in 2004. As of a press release in October 2011 from the UN-backed annual International Awards for Liveable Communities, Pfaffenhofen an der Ilm was saluted by judges for the quality of its environmental best practice. The Bavarian town of 23,000 people was also named the most liveable city with a population between 20,000-75,000.