The Welsh League Division One is the second tier of the Welsh football pyramid for clubs from south Wales.
North and mid-Wales has the parallel Huws Gray Alliance.
At the end of the season the champions of both second tier leagues are eligible for promotion to the Welsh Premier, if they can gain the FAW's domestic club licence. If not, the runner-up may also qualify.
Teams that have gained promotion from the Welsh League in recent years are Neath FC (2007), Grange Harlequins (2005), Llanelli (2004), Port Talbot (2000), Haverfordwest County (1997) and Carmarthen Town (1996).
The league has operated with a reduced number of 16 clubs since season 2010/11.
Caerleon, Monmouth Town and Tata Steel were promoted to Division One in 2012 with Caerau (Ely), Cardiff Corinthians and Cwmaman Institute relegated.
Barry Town, Briton Ferry, Cwmbran Town, Grange Quins, Haverfordwest County and UWIC (formerly Inter Cardiff) are previous members of the Welsh Premier.