Saint-Ouen-l'Aumône is a commune in the northwestern suburbs of Paris, France. It is located 27.6 km (17.1 mi) from the center of Paris, in the "new town" of Cergy-Pontoise, created in the 1960s.
Saint-Ouen-l'Aumône is served by two interchange stations on Paris RER C line and on the Transilien Paris – Nord suburban rail line: Saint-Ouen-l'Aumône – Liesse and Saint-Ouen-l'Aumône.
Saint-Ouen-l'Aumône is also served by two other stations on the Transilien Paris – Nord suburban rail line: Épluches and Pont-Petit.
Finally, Saint-Ouen-l'Aumône is also served by Saint-Ouen-l'Aumône – Quartier de l'Église station on the Transilien Paris – Saint-Lazare suburban rail line.