Snaefell Mountain Course or Mountain Course is a road-racing street circuit used for the Isle of Man TT and Manx Grand Prix Races held in the Isle of Man from 1911 and 1923 respectively. The racing is held on public roads closed for racing by an Act of Tynwald (the parliament of the Isle of Man). It is the oldest motor-cycle racing circuit still in use.
The course is 37.733 miles (60.73 km) in length and the start-line is situated on the A2 Glencrutchery Road in the town of Douglas. The racing circuit is based on a number of public roads on the Isle of Man including the primary A2 Douglas to Ramsey road, A1 Douglas to Peel road, A3 Castletown to Ramsey Road and the primary A18 Snaefell Mountain Road. The highest point of the course is situated on the primary A18 Mountain Road between the Bungalow and Hailwood's Height at spot height 422 metres (1,385 ft) above sea level.
Official Lap Records:
The official lap record for the Snaefell Mountain Course is 17 Minutes and 12.30 seconds at an average speed of 131.578 mph (211.754 km/h) set by John McGuinness during the 2009 Senior TT Race. The race record is held by Steve Plater in 1 hour, 45 minutes and 53.15 seconds; an average race speed of 128.278 mph during the same 6 lap (236.38 Miles) 2009 Senior TT race.
The lap record for the Sidecar TT is 19 minutes and 24.24 seconds at an average speed of 116.667 mph set by Nick Crowe and passenger Daniel Sayle during the 2007 Sidecar Race B.The race record for the Sidecar TT is 58 minutes and 59.28 seconds at an average race speed of 115.132 mph for 3 laps (113.00 miles) of the course, held by Dave Molyneux and Daniel Sayle during the 2009 Sidecar Race A.In the 2006 TT practices New Zealander Bruce Anstey achieved the unofficial current top speed record of 206 mph (332 km/h).at the end of Sulby straight on a Suzuki 1000cc machine. This speed value was registered by the on-board datalogging equipment and can not be considered as an official record.
The same course has also been used for cycle racing, including individual time trials and, from 1936, the Manx International massed-start road race. The first race held on the 18 June 1936 was won by Charles Holland of the Midland Cycle and Athletics Club in 1 hour, 42 minutes and 57 seconds for one lap of the Mountain Course.