Salm-Horstmar was a short-lived Napoleonic County in far northern North Rhine-Westphalia, Germany, located around Horstmar, to the northeast of Münster. It was created in 1803 for Wild- and Rhinegrave Frederick Charles Augustus of Salm-Grumbach following the loss of Grumbach and other territories west of the Rhine to France. It was mediatised to the Kingdom of Prussia in 1813 and the Wild- and Rhinegrave was awarded a princely title within Prussia three years later.