Southern 100

Southern 100 Road Races
Billown Circuit
Venue Castletown, Isle of Man
Date 2nd Week of July (Mon-Thurs)
Type Road Course
Clerk of the Course Giles Olley
Event Organiser Southern 100 M.C.R.C. Ltd
Event Promoter Southern 100 M.C.R.C. Ltd
Principal sponsor Isle of Man Department for Enterprise
History
First races 1955
First winners (1955) Dave Chadwick (250 cc)
Derek Ennett (350 cc)
Terry Shepherd (500 cc)
Most wins Ian Lougher (32)
Lap record Dean Harrison
2 minutes, 10.835 secs
116.941 mph (188.198 km/h), 2022

The Southern 100 is a motorcycle road racing event held on the Isle of Man in July of each year. The event was first held in 1955, with three races for different classes of solo motorcycles; the 2015 calendar included twelve races for various classes. The participants compete on the Billown Circuit in the south of the island, starting and finishing at Castletown.