Counties 1 Southern South

Counties 1 Southern South (formerly known as Southern Counties South) is a level 7 league in the Rugby Football Union South West Division, the rugby union governing body for South West England, part of the Rugby Football Union. When league rugby first began in 1987 it was a single league known as Southern Counties but in 1996 the division was split into two regional leagues: Southern Counties North (now Counties 1 Southern North) and Southern Counties South. Counties 1 Southern South currently sits at the seventh tier of club rugby union in England and primarily features teams based in Dorset and Wiltshire.

The league champions at the end of the season are promoted to Regional 2 South Central while the runners up face the runners up from Southern Counties North for their place. Relegated teams tend to drop to either Counties 2 Dorset & Wilts North, Counties 2 Dorset & Wilts South or Counties 2 Dorset & Wilts Central depending on geographic placement. As of the 2022–23 season, with the RFU league restructuring, lower XVs are able to play in Counties 1 Southern South.