Saint-Leu-d'Esserent (French pronunciation: [sɛ̃ lø dɛsʁɑ̃]) is a commune in the Oise department in northern France.

[3] Saint Leu is notable for 3,000 square metres (32,000 sq ft) of mushroom quarries under the Thiverny plateau.

[4] During World War II, the quarries were one of three major underground V-1 flying bomb storage depots.

In addition to the quarries, the facility included blockhouses, bunkers, flak emplacements and railway links.

Allied intelligence firmly identified late in June 1944 that Saint-Leu-d'Esserent and Nucourt were V-1 storage depots.