Businesses
- J and C Boyd and Company Limited
- J and H Wedd and Company Limited
- J and J Colman Limited
- J and J Doyle
- J and LF Goodbody Limited, jute spinners and manufacturers
- J Bibby and Sons Limited
- J Donohoe Limited
- J Doyle and Son Limited
- J Elliot and Sons, provision merchants
- J Ferguson and Company, hairdressers and perfumers
- J Griffin
- J Hubbard Clarke
- J Kerr and Sons
- J Kidd and Company Limited
- J Lyons and Sons
- J McDonnell
- J Nagle and Company, wine and spirit merchants
- J Norton and Sons
- J Pullar and Sons Limited
- J Sears and Company Limited
- J Sinclair
- James Barber, chandler and tobacconist
- James Carter and Company
- James Crean and Son
- James Duffy and Company Limited
- James Gibson and Son
- James H Woods and Son
- James Hill and Son
- James J Mullan, solicitor
- James Lough and Son
- James McCullagh Son and Company
- James Methven Son and Company Limiited
- James Methven Son and Company Limited
- James O'Dwyer and Company
- James Pim and Son
- James Spicer and Sons Limited
- James T Jameson and Sons, general printers and advertising contractors
- James Walker (Dublin) Limited
- James Weir and Company Limited
- James Winstanley
- JB Curran
- JC Parkes and Sons Limited
- JE Stanley, photographer
- Jefferson and Company, manufacturers agents
- Jervis Street Hospital
- JF Haig and Company
- JF Lanigan and Company
- JF Yates and Company, coal merchant
- JG Mooney and Company Limited, wine and spirit merchants
- JH Hunter and Company Limited
- JH Sankey and Son Limited
- JH Walsh and Company, solicitors
- JH Webb and Company
- JJ Carroll and Company
- JJ Farrell, grocer
- JJ Galloway, solicitors
- JJ Keating, cycle and motor dealer
- JJ Kelly and Company, cycle agents
- JJ Lalor, Catholic art repository
- JJ Lanigan and Company
- JJ Stafford and Sons Limited
- JL Byrne Limited
- JM Greene and Sons
- JM Ross Todd and Company, solicitors
- JM Smith and Company
- John A Clarke and Company
- John A Sinnott and Company, solicitor
- John Bolger and Company, draper
- John Cavey, grocer
- John Dempsey and Company
- John Egan and Company
- John Fitzsimons and Son, fruiterer
- John G Lidwell, solicitor
- John J Shiel, solicitor
- John Jameson and Son Limited, distillery
- John Kane, ecclesiastical art metal worker
- John Knight Limited
- John Lambert and Son
- John Leacy
- John Locke and Company Limited
- John McDonald, solicitor
- John McDowell, jeweller and watchmaker
- John McDowell, solicitor
- John Morgan and Sons
- John Morris
- John Plunkett and Company Limited, maltsters
- John Power and Son Limited, distillery
- John Purcell Limited
- John SB Vanston, solicitor
- John Symons and Company Limited
- John Tyler and Sons Limited, boot manufacturers
- John V Traynor and Company, brush and comb makers
- John Wallis and Sons, mail cart contractors
- Johnston Mooney and O'Brien
- Jordan Brothers, grocers
- Joseph Crosfield and Sons Limited
- Joseph Downes, bakery
- Joseph Garrett and Company, tea and sugar merchants
- Joseph J McGreevy, wine and spirit merchant
- Joseph Lucas Limited
- Joseph Newman, scale and beam maker
- Joseph Rank Limited
- JP and R Goodbody
- JP Tyndall and Company
- JT Davis Limited
- Junior Army and Navy Stores Limited
- Jury and Colton
- JW Elvery and Company Limited