Map sheet number OL 34 in the OS Explorer series covers Horsham, Cranleigh, Crawley & Billinghurst. Highlights of the area include: the River Ouse, River Arun & River Adur, Low Weald & the western area of High Weald, & corners of the Sussex Downs & South Downs. This map replaces the previous OS Explorer map 134 for this area With this map you will receive a code for use on your i OS or Android smartphone or tablet. Find our more at Mobile Download FAQ. The OS Explorer map for Crawley & Horsham is available in both the standard paper version & weatherproof ' Active' version.