The Corbetts are mountains in Scotland between 2,500 and 3,000 feet in height with a drop of 500 feet all round. They are named after John Rooke Corbett who compiled the original list. The complete list of Corbetts can be found in the Munro Tables published by the Scottish Mountaineering Club who also publish 'The Corbetts and Other Scottish Hills'. (www.smc.org.uk)
Two of the mountains listed have the same height but the drop between them is less than the stipulated 500 feet. They are Sgurr a'Bhac Chaolais and Buidhe Bheinn between Kinloch Hourn and Glen Shiel. In my opinion you need to climb both summits to claim this one Corbett. However others disagree and some actually count these twin hills as two separate Corbetts.
Up to September 2009 there were 219 Corbetts (some say 220 - see above) but a recent survey arranged by the Munro Society and apparently ratified by Ordnance Survey, Great Britain's Mapping Agency, found that Sgurr nan Ceanaichean in Glen Carron, Wester Ross was in fact only 913.43 metres in height. It was therefore relegated from being Munro to Corbett status. This means that there are 220 Corbetts, others may say 221. However you decide whether it is 220 or 221.
Corbett Tops have the same height criteria as Corbetts but only have a drop of at least 30 metres all round. They include all the Corbetts and therefore there are around 670 Corbetts and Corbett Tops.
A person climbing the Corbetts is called at Corbett Bagger while someone who has climbed all the Corbetts is called a Corbetteer.
A list of those that have completed the Corbetts is maintained at this web site.