The Château de Courson was built in 1676 in Courson-Monteloup (the postal code is 91680; INSEE code 91186), on the south-west outskirts of Paris, France. It is in the Essonne département of the Île-de-France région.

Originally the home of the Lamoignon family, the château has been in the same family since the 18th century. Its historic park was laid out in formal style by a pupil of André Le Nôtre in the 18th century. During the 19th century the gardens were twice remodelled, first around 1820 for the Duc de Padoue by the landscaper Berthault, then again around 1860 by the Bülhers, who laid out many French parks and gardens, including those of Rennes, Lyon and Bordeaux.

It is now most famous as the venue for the Journées des Plantes de Courson. These extremely popular plant fairs have been held in mid-October since 1983. Since 1987 a spring plant fair has been held in mid-May.