Paderborn became a part of Prussia in 1802. After the Napoleonic wars when Prussia created the province Westphalia it split Paderborn into two districts - Paderborn and Büren. In 1975 these two districts were joined together again to make the current Paderborn district.
The red cross in the top of the coat of arms symbolizes the clerical state Paderborn. The wavy line below stands for the rivers in the district, especially the Lippe River. The symbol in bottom is from the Lords of Büren.