In 1870-72, John Marius Wilson's Imperial Gazetteer of England and Wales described Llansadwrn like this:
LLANSADWRN, a parish, with a village, in the district of Bangor and county of Anglesey; 2½ miles W of Beaumaris, and 3½ NNE of Llanfair r. station. Posttown, Beaumaris, Anglesey. Acres, 2,891. Real property, £2,660. Pop., 410. Houses, 84. The property is divided among a few. There are some Druidical and other antiquities. The living is a rectory in the diocese of Bangor. Value, £381. Patron, the Bishop of Bangor. The church is dedicated to St. Sadwrn, and is good.
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 Llansadwrn has changed, please see our redistricted information for the modern district of the Isle of Anglesey. More detailed statistical data are available under Units and statistics, which includes both administrative units covering Llansadwrn and units named after it.
GB Historical GIS / University of Portsmouth, History of Llansadwrn in The the Isle of Anglesey | Map and description, A Vision of Britain through Time.
Date accessed: 05th February 2016
Click here for more detailed advice on finding places within A Vision of Britain through Time, and maybe some references to other places called "Llansadwrn".