Caterham is a town in the Tandridge District of Surrey, England. The town is geographically divided into two sections: Caterham on the Hill and Caterham Valley that includes the main town centre. The town lies close to the A22, 21 miles from Guildford and a few miles south of Croydon, in a valley cut into the dip slope of the North Downs. Caterham on the Hill is above the western side of the valley. The resident population of Caterham is 20,957 people.