Trefonen is a small village located approximately three miles (4.8 km) south-west of Oswestry, and three miles east of the England-Wales border, in Shropshire, England. The name translates into "village of the ash trees" in English. In 2001, the total population was 1,798, but there has been considerable housing development since that time. The village currently comprises over 700 households, a village hall with playing fields and play area, a parish church, one public house—the Barley Mow, one shop, pre school, and a primary school. At the 2011 Census the population details are listed under Oswestry Rural.
The eighth century earthwork Offa's Dyke ran through the village and it is still visible today, in small sections, running adjacent to Chapel Lane. The Offa's Dyke Path, tracing the route of the structure, also runs directly through the village. Each summer the more contemporary Trefonen Hill Walk is organised by local residents to raise money for charitable causes.