The first Southern 100 Road Races took place in 1955. The three races covering the classes of 250cc, 350cc, and 500cc attracted 73 entries. The 250cc and the 350cc were the traditional classes of their day, raced over 6 laps covering 25 miles. The 500cc, was the premier race over a massive 24 laps covering a distance of 100 miles. By 1958, the Southern 100 Races had gained national status and in 1962, sidecars were added to the races. In 1968, the Solo Championship was started and in 1969 the Southern 100 Races were part of the British Championship and later in 1992 and 1993 they were included in the Irish Regal Championships.
The Southern 100 Races now feature mass start solo, sidecar and classic motorcycle races, which start and conclude the TT Festival. Competitors race on the main roads of the Billown Circuit covering 4.25 miles. The races are run by the Southern 100 Club in Castletown and known as the 'Friendly Meeting'.
The club will introduce new electric timing (optional) for 2003 with the hope of moving to them permanently in 2004. Everyone should know the benefits of an electric system, which include quick results, intervals between riders, and live racing results just to name a few.