The Lower Rhenish–Westphalian Circle was an imperial circle of the Holy Roman Empire. It comprised territories of the former Duchy of Lower Lotharingia, Frisia and the Westphalian part of the former Duchy of Saxony. The circle was made up of numerous small states, however the Counts De la Marck were able to collect a significant number of territories, the United Duchies of Jülich-Cleves-Berg, from 1521 on. The Empire's largest ecclesiastical territory was held by the Prince-Bishops of Münster.