In 1870-72, John Marius Wilson's Imperial Gazetteer of England and Wales described Heneglwys like this:
HENEGLWYS, a parish in the district and county of Anglesey; adjacent to the river Cefni, 3 miles W of Llangefni r. station, and 4½ N of Bodorgan. Post town, Llangefni, Anglesey. Acres, 2, 062. Real property, £2, 101. Pop., 510. Houses, 114. The property is divided among a few. The living is a rectory, united with the p. curacy of Trewalchmai, in the diocese of Bangor. Value, £383. Patron, the Bishop of Bangor. The church was rebuilt in 1845, and has a very ancient font.
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 Heneglwys 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 Heneglwys and units named after it.
GB Historical GIS / University of Portsmouth, History of Heneglwys in The the Isle of Anglesey | Map and description, A Vision of Britain through Time.
Date accessed: 27th June 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 "Heneglwys".