Sologne (Secalaunia from Lat. secale, rye), a region of north-central France extending over portions of the départements of Loiret, Loir-et-Cher and Cher. Its area is about 5,000 square kilometres (1,900 sq mi), and its boundaries are on the north the river Loire, on the south the Cher and on the east the districts of Sancerre and Berry.
The Sologne is watered by the Cosson and the Beuvron, tributaries of the Loire, and the Sauldre, an affluent of the Cher, all three having a west-south-westerly direction. The pools and marshes which are characteristic of the region are due to the impermeability of its soil, which is a mixture of sand and clay.