[5] The ridge line of Keppel Gate[6] is part of a large area of former Crown Commons grazing mountain land known as 'Slieau Lhoost.

This includes sections of the North Atlantic sub-montane heath found on different sections of Mountain Lands in the Isle of Man as a European Union community "priority habitat",[13] as described by Annex 1 of the EU Habitats Directive[14] and also the UK Guidelines for Selection of Biological Specific Scientific Interest (SSSI's).

[15] The heath and heather moorland of the Northern Uplands[16] of the type found at Keppel Gate, including Slieau Ree Mountain and Kate's Cottage is an Area of Specific Scientific Interest (ASSI) and further nearby sections of mountain land at Keppel Gate are defined as a "biodiversity" and a upland conservation "hot-spot.

[20] Additional meanings is that the name Keppel Gate originates from the Scandinavian for Old Norse: Kappafjall (The Champion or Hero's mountain).

Built over a period of time in the Nineteenth century from a number of horse paths, ancient rights of way of the Regiam Viam (Royal Way)[27] (archaic|Manx: Bayr-yn-Ree) and a series of pre-existing carting-tracks and incomplete stone mountain paths which traversed mountain land, peat bogs and hillside sections.

[41] The Auto-Cycle Union proposed in 1921 to move the Isle of Man TT Races to the Continental Circuit de Spa-Francorchamps in Belgium.

[42][43] After an offer made by the Belgium Government the move was considered by the Auto-Cycle Union due to financial reasons, organisational problems and criticism of the Isle of Man TT Mountain Course.

[45][46] The section of A18 Snaefell Mountain Road from the Thirty-Third Corner to near Keppel Gate was widened and road-side fence post relocated below road level for the 1947 Isle of Man TT Races[47] after a fatal accident to Peter M. Aitchison a competitor during the 1946 Senior Manx Grand Prix.