Southern 100

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.

History
In 1955, the inaugural Southern 100 held events for each of the two traditional classes, the 250 cc and the 350 cc, over six laps with a race distance of 25 miles. A 500 cc race was also included as the feature race with 24 laps, totalling in excess of 100 miles.

The meeting that year had 73 entrants, with the first race held, the 350 cc event, won by Manxman Derek Ennett.

In 1958, the event was granted "National Status" and eleven years later was included in the British Championships. The races were part of the Irish Regal Championships in 1992 and 1993, and is now one of five FIM-sanctioned International meetings in the British Isles. Sidecar racing was introduced in 1962 and currently constitutes two of the twelve scheduled races.

Ian Lougher has achieved the most solo-machine victories, with 32 wins, followed closely by Joey Dunlop with 31. Dave Molyneux leads the Sidecar victories, with 15. The Billown Circuit has been lapped with an average speed over 100 mph on a number of occasions, but it was first achieved by Dave Leech in the 1989 Southern 100 Solo Championship Race riding a 1000 cc Yamaha at an average speed of 100.26 mph.

The 2023 meeting was abandoned following a serious incident on 11th July 2023 where a competitor and marshal were killed.