Bouldnor Cliff is a submerged prehistoric settlement site in the Solent. The site dates from the Mesolithic era and is in approximately of water just offshore of the village of Bouldnor on the Isle of Wight in the United Kingdom. The preservation of organic materials from this era that do not normally survive on dry land has made Bouldnor important to the understanding of Mesolithic Britain, and the BBC Radio 4's Making History programme described it "probably Europe's most important Mesolithic site" albeit concealed under water.