Slater's 1868 Directory for North Wales
(There were only letterpress printers this far back in time)
John Brown, 7 Caellepa
Catherall & Nixon, 267 High St
John Kenmuir Douglas (and Publishers), 276 High St
John Mendus Jones, 238 High St
Robert Jones, Bethesda
Thomas Jones, 143 High St
John Williams, 10 Chapel Street, Upper Bangor
Pigot & Co's Directory of North Wales 1835 Printers--Letterpress
John Brown, Castle St
Richard Jones, Friars Place
Peter Paul, Dean St
Newspapers
The North Wales Chronicle, every Tuesday, publisher John Brown, Castle St
1881 Census
Benjamin Williams, Printer/compositor, aged 33, 39 Kinmel St., Rhyddlan, Flints
1841 BANGOR CENSUS
Robert Jones, 36, Letterpress Printer, High Street
Robert Hunter, 35, Editor, North side High Street
1851
George Henry Hughes, Printer/compositor, Glanrafon, b. Caernarvon
Johm Owen James, Printer, James Street, b. Meirioneth
William Price, Printer/compositor, James Street, b. Lan/Manchester
Edward Kingsman Jones, Printer/compositor, Pendre, b. Flintshire
Edward Parry Jones, Printer/compositor, Holyhead Cottages, b. Anglesey
Hugh Williams, Editor/Printer, Holyhead Cottages, b. Meirionethshire
James Wardle, Printer/compositor, Panton Street, b. Lan/Manchester
John Williams, Compositor, Drum Street, b. Caernarfon
1891 census
Edwin Iorwerth Rowlands, Compositor, 23, b. Bangor, 1 Thomas Buildings
Ivor Pugh Rowlands, Apprentice Printer, 18, b. Bangor, 1 Thomas Buildings
David Gray, Printer/compositor, 27, b. Llandwrog, 1 Caellepa
Another list of links for reference
http://communication.ucsd.edu/bjones/Books/printech.html
http://www.ideafinder.com/history/inventions/story039.htm
Newspaper Library Catalogue Search by title, or by name of town/county and it will show the range of newspapers held there that covered that place overtime.
THE VICTORIAN WEB ... Chronological list of events in the development of the Printing Trade http://www.victorianweb.org/victorian/technology/print/printchron.html
1871 census, Bangor, Caerns, Pg. 23, Schedule 122
4 Vron Square
Jane Horton, head, widow, 64, Washerwoman, b. Beddgelert
Davis Horton, son, 24, single, Compositor, Montgomery
Mary Jane Griffiths, neice, 12, Bangor, Caerns
Ellin Williams, single, 23, servant, Llandwrog, Caerns