Welsh Football League Division One

The Welsh Football League Division One, known as the Nathanielcars.co.uk Welsh League First Division for sponsorship reasons, is a football league in South Wales. It forms the top division of the Welsh Football League and the second level of the Welsh football league system.

If the team which finishes top of the Division has good enough ground facilities, it is promoted to the Welsh Premier League and is replaced by one of the two teams finishing bottom of the Premiership. If the Division champions' ground doesn't meet Premiership standards, then the team which finished second may be promoted. The team finishing in bottom position is relegated to the Welsh Football League Division Two.

Since its inception in 1904 it has always been the top flight of the Welsh League, or the Rhymney Valley League and Glamorgan League as it was known until 1912.

This division has changed its name on numerous occasions, which includes Premier Division and National Division.

In 1992 it became level two of the Welsh Football Pyramid following the creation of the Welsh Premier League.

Members for 2016–17

 * Afan Lido
 * Barry Town United
 * Caerau (Ely)
 * Caldicot Town
 * Cambrian & Clydach Vale
 * Cwmbran Celtic
 * Goytre (Monmouthshire)
 * Goytre United (Port Talbot)
 * Haverfordwest County (relegated from the Welsh Premier League)
 * Monmouth Town
 * Pen-y-Bont
 * Port Talbot Town (demoted from the Welsh Premier League)
 * Risca United
 * Taff's Well
 * Ton Pentre
 * Undy Athletic