Knocknapeasta's prominence qualifies it to meet the British Isles Marilyn classification, being the only other 3,000 foot Reek alongside Carrauntoohil to meet the 150 metre Marilyn prominence threshold. Cnoc na Péiste also exceeds the P600 prominence threshold of , which classes it as a Major mountain. Cnoc na Péiste also meets the Arderin, Simm and Hewitt classifications. Knocknapeasta ranks as the second-highest mountain in Ireland on the MountainViews Online Database, 100 Highest Irish Mountains, where the prominence threshold is over 100 metres.