In 1870-72, John Marius Wilson's Imperial Gazetteer of England and Wales described Middleton on Sea like this:
MIDDLETON, a parish in Westhampnett district, Sussex; on the coast, 2½ miles E of Bognor r. station. It includes the hamlet of Elmer; and its Post town is Bognor. Acres, 859; of which 213 are submerged every tide. Real property, £665. Pop., 89. Houses, 16. The property is divided among a few. Much land has been removed by encroachment of the sea. The living is a rectory in the diocese of Chichester. Value, £180. Patron, George H. Roe, Esq. The old church was swept away by the sea; and the present church was built in 1849.
A Vision of Britain through Time includes a large library of local statistics for administrative units. For the best overall sense of how the area containing Middleton on Sea has changed, please see our redistricted information for the modern district of Arun. More detailed statistical data are available under Units and statistics, which includes both administrative units covering Middleton on Sea and units named after it.
GB Historical GIS / University of Portsmouth, History of Middleton on Sea, in Arun and Sussex | Map and description, A Vision of Britain through Time.
Date accessed: 23rd October 2014
Click here for more detailed advice on finding places within A Vision of Britain through Time, and maybe some references to other places called "Middleton on Sea".