The town was named after
Saint Audoin, a famous 7th century AD Frankish bishop. On 1 January 1860, the city of Paris was enlarged by annexing neighbouring communes. On that occasion, a part of the commune of Saint-Ouen was annexed to the city of Paris. At the same time, the commune of La Chapelle-Saint-Denis was disbanded and divided between the city of Paris, Saint-Ouen, Saint-Denis, and
Aubervilliers. Saint-Ouen received a small part of the territory of La Chapelle-Saint-Denis. The commune of
Montmartre was also disbanded; the city of Paris annexed most of Montmartre, but Saint-Ouen did receive a small northern part of the territory of that commune. The
Hôtel de Ville was completed in 1868. ==Population==