Montigny-lès-Cormeilles

The Fort de Cormeilles-en-Parisis was constructed between 1874 and 1877 as part of a new plan for the defense of Paris developed by General Raymond Adolphe Séré de Rivières, near the town of Cormeilles-en-Parisis. During the Franco-Prussian War, German troops had used the hill upon which the fort sits as a spotting and firing location, ideal for the siting of new rifled guns whose range was increased over old-fashioned smooth-bore guns. These weapons could attack Paris from Cormeilles, so a new outer ring of forts had to be built outside the first ring of forts built in 1840–1860 to deny the area to enemy gunners. The Séré de Rivières system was designed as a response to these technological innovations, and to the loss of French territories in Alsace and Lorraine.

Montigny–Beauchamp is a station between Montigny-lès-Cormeilles and Beauchamp, in the northwestern suburbs of Paris. It is served by Transilien regional trains from Paris to Pontoise, and by RER rapid transit.

Beauchamp (French pronunciation: [boʃɑ̃] ) is a commune in the Val-d'Oise department in Île-de-France in northern France.

Cormeilles-en-Parisis (French pronunciation: [kɔʁmɛj ɑ̃ paʁizi] (listen), literally Cormeilles in Parisis) is a commune in the Val-d'Oise department in Île-de-France in Northern France. Inhabitants are called Cormeillais(e).

The canton of Franconville is an administrative division of the Val-d'Oise department, Île-de-France region, northern France. Its borders were modified at the French canton reorganisation which came into effect in March 2015. Its seat is in Franconville.It consists of the following communes: Cormeilles-en-Parisis Franconville

La Frette-sur-Seine (French pronunciation: [la fʁɛt syʁ sɛn] (listen), literally La Frette on Seine) is a commune in the Val-d'Oise department in Île-de-France in northern France.

The Communauté d'agglomération Val Parisis is the communauté d'agglomération, an intercommunal structure, in the northwestern suburbs of Paris. It is located in the Val-d'Oise department, in the Île-de-France region, northern France. It was created in January 2016. Its seat is in Beauchamp. Its area is 87.2 km2. Its population was 278,166 in 2018.

Herblay-sur-Seine (French pronunciation: [ɛʁblɛ syʁ sɛn], lit. "Herblay-on-Seine"; before 2018: Herblay) is a commune in the Val-d'Oise department in the Île-de-France region in Northern France. It is located 20.2 km (12.6 mi) from the centre of Paris, in its northwestern outer suburbs, on the departmental border with Yvelines. It is twinned with Yeovil, England.

The canton of Taverny is an administrative division of the Val-d'Oise department, Île-de-France region, northern France. Its borders were modified at the French canton reorganisation which came into effect in March 2015. Its seat is in Taverny.It consists of the following communes: Beauchamp Bessancourt Pierrelaye Taverny

Franconville (French pronunciation: [fʁɑ̃kɔ̃vil] (listen)) is a commune in the Val-d'Oise department in Île-de-France in northern France. It is a northwestern suburb of Paris, located 17.1 km. (10.6 miles) from the center of Paris.

The canton of Herblay-sur-Seine (before 2021: Herblay) is an administrative division of the Val-d'Oise department, Île-de-France region, northern France. Its borders were modified at the French canton reorganisation which came into effect in March 2015. Its seat is in Herblay-sur-Seine.It consists of the following communes: La Frette-sur-Seine Herblay-sur-Seine Montigny-lès-Cormeilles

Franconville – Le Plessis-Bouchard is a station in Franconville, a northwestern suburb of Paris, France. It is served by Transilien regional trains from Paris to Pontoise, and by RER rapid transit.