At the 2011 census the population of the parish was 207.[1]
In 1086, the settlement was recorded in the Domesday Book as Wisdelea.[2]
Lea-by-Backford, including part of the hamlet of Dunkirk, was a township within the Backford parish of the Wirral Hundred. The population was recorded at 70 in 1801, 91 in 1851, 73 in 1901, 233 in 1951 and 191 in 2001.[3]