C
- Cappenberg Abbey (Kloster Cappenberg), later Schloss Cappenberg (Cappenberg Castle), Selm: Premonstratensian Canons 1122–1802/03
- Clarenberg Priory (Kloster Clarenberg), Hörde, Dortmund: Poor Clares 1339–1583: secular canonesses 1583–1812
- Clarholz Abbey (or Priory) (Stift or Kloster Clarholz), Herzebrock-Clarholz: Premonstratensian canons before 1146–1803 (fdd 1133 in Lette in Oelde as a double monastery, but separated by 1146, and canons moved to Clarholz, while nuns stayed in Lette)
- Cleves Abbey or Priory (Stift Kleve), Cleves: canons 1334–1802
- Cologne:
- Redemptorist Fathers, Cologne (dates tbe)
- Alexian Hospital, Cologne (Alexianer Krankenhaus Köln): Alexians 1300–today
- St. Anthony's Hospital, Cologne (Antoniterkloster; church now the Antoniterkirche) 1350 x 1378–1794
- Cologne Charterhouse (Kartäuserkloster Köln): Carthusians 1334–1794
- St. Elisabeth's House, Cologne: Olpe Sisters (dates tbe)
- St. Elisabeth's Convent, Cologne: (Cellitinnen zur heiligen Elisabeth): Cellite Sisters (dates tbe)
- St. Gertrude's Priory (Kloster Sankt Gertrud): tbe
- St. Mary's Convent, Cologne (Cellitinnen zur heiligen Maria): Cellite Sisters (dates tbe)
- Convent of the Cellite Sisters of the Rule of St. Augustine, Cologne (Cellitinnen nach der Regel des hl. Augustinus): Cellite Sisters (dates tbe)
- Corvey Abbey (Kloster Corvey), Höxter: Benedictine monks 822–1807
Read more about this topic: List Of Christian Religious Houses In North Rhine-Westphalia