Oeynhausen is the name of an old Westphalian noble family. The men belonged to the nobility of Oyenhausen in Paderborn region. The spelling of the name varies from Oyenhausen, Oynhausen, Oinhausen, Oeynhausen, Oenhausen to Oeynhausen.
Branches of the family still exist today. In ancient annals of the name Oeynhausen is interpreted as Einhaus. It is first mentioned the sex with Berhardus villicus the Oienhusen in the 1. More 1237 issued document. Oeynhausen, the name-giving headquarters, is today a village near town Nieheim in a circle Hoexter. The continuous strain range starts at 1300 mit Johann von Oynhausen.
Oeynhausen, By Julius: History of sex in Oeynhausen, Bd. 1-2 Documents and calendar entries, Paderborn: Ferdinand Schöningk, 1870
Oeynhausen, By Julius: History of sex in Oeynhausen, Bd. 4 Pedigrees, Frankfurt: Wilhelm Rommel, 1889