Monmouth (/ˈmɒnməθ/ MON-məth; Welsh: Trefynwy meaning "town on the Monnow") is a traditional county town in Monmouthshire, Wales. It is situated where the River Monnow meets the River Wye, within 2 miles (3.2 km) of the border with England. The town is 36 miles (58 km) northeast of Cardiff, and 127 miles (204 km) west of London. It is within the Monmouthshire local authority, and the parliamentary constituency of Monmouth. According to the 2001 census, its population was 8,877, increasing to 10,508 at the 2011 census.
The town was the site of a small Roman fort, Blestium, and became established after the Normans built a castle here after 1067. Its mediaeval stone gated bridge is the only one of its type remaining in Britain. The castle later came into the possession of the House of Lancaster, and was the birthplace of King Henry V in 1387. In 1536, it became the county town of Monmouthshire.
Monmouth later became a tourist centre at the heart of the Wye Valley, as well as a market town. It now acts as a shopping and service centre, and as a focus of educational and cultural activities for its surrounding rural area.