Rhencullen (Manx: ‘holly ridge’) (locally /ˈrənˈkðlənˈ/)[1] including Birkin's Bend[2] is adjacent to the 17th milestone of the TT course, on the primary A3 Castletown to Ramsey road in the Isle of Man.

The area is dominated by the farmland at Ballarhenny and the Bishop's Demesne of Bishopscourt, including Birkin's Bend, 'Cloudy Lane'[3] and Rhencullen Hill.

The disused Peel to Ramsey line of the former Manx Northern Railway runs parallel to the A3 road at Rhencullen in a cutting, now part of the Raad ny Foillan long-distance footpath.

The Rhencullen section was part of the 37.50 Mile Four Inch Course for the RAC Tourist Trophy automobile races held in the Isle of Man between 1908 and 1922.

[8] During an early morning practice session for the 1927 Isle of Man TT races, Archie Birkin, riding a 500 cc McEvoy motor-cycle, crashed fatally at Rhencullen after swerving to avoid a collision with a fish-van being driven on open public roads.