Map sheet number OL14 in the OS Explorer series covers Monmouth, Ross-on-Wye, Chepstow, the Forest of Dean & the Wye Valley. Other highlights of the area include: the River Severn, Vale of Berkeley, the Offa's Dyke Path & the Wye Valley Walk. 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 Wye Valley & Forest of Dean is available in both the standard paper version & weatherproof ' Active' version.