Named after the Porte de Saint-Ouen, the gate on the road to Saint-Ouen-sur-Seine.
One of 17 gates in the Thiers wall, it was built around 1840 on land of the old commune of Montmartre; since the annexation law of 16 June 1859 it has marked the edge of Paris. The town beyond is named after saint Ouen, bishop of Rouen, who died in King Dagobert's palace there; it became officially Saint-Ouen-sur-Seine in November 2018.