"BLACKBOURN, a hundred in Suffolk. It lies between Norfolk on the N, Hartismere hundred on the E, and Lackford hundred on the W; and contains Great Ashfield parish, thirty-two other parishes, and part of another. Acres, 63,857. Pop., 15,703. Houses, 3,302."
(From John Marius Wilson, Imperial Gazetteer of England and Wales (1870-72).)
In 1836, White's Description of the Poor Law Unions and Registration Districts shows this Hundred to be served by the Registration Districts of Stow and Thetford and Thingoe.
STOW RD in 1836 - 34 parishes comprising 14 in Stow Hundred, 11 in Blackbourn Hundred, and 9 in Thedwestry Hundred. The Union is divided into 3 sub-districts:- Stowmarket, Rattlesden, and Walsham-le-Willows.
THETFORD RD in 1836 - 34 parishes comprising the 3 parishes of Thetford, namely St. Peters, St. Cuthberts and St Marys, Kilverstone, Croxton, East Wretham, West Wretham, Brettenham, Rushford,Hethwold, Northwold, Santon, Hockwold-cum-Wilton, Feltwell, Mundford, Lynford, West Tofts, Sturston, Cranwich, and Weeting-cum-Broomhill all in Norfolk. Also the parishes of Santon Downham, Brandon, Barnham, Fakenham-Magna, Euston, Honnington, Sapiston, Coney Weston, Barningham, Weston Market,Hepworth, Thelnetham, Hopton and Knettishall in Blackbourn and Lackford Hundreds in Suffolk. Thetford Union is divided into 2 sub-districts :-Thetford and Methwold.
THINGOE RD in 1836 - 46 Parishes of which 15 are in Thedwestry Hundred, 10 in Blackbourn Hundred, 18 in Thingoe Hundred plus 3 in Risbridge Hundred viz. Chedburgh, Denham, and Depden.
See also Brett Langston's Suffolk Registration Districts.
Historical information about boundaries and administrative areas for Blackbourne Hundred is available from A Vision of Britain.