- 1 Ackers (Firm)
- 1 Ackers Coffee Candies Pastry
- 8 Acorns
- 1 Acrobats
- 18 Acting
- 1 Acting Inspector of Police
- 4 Activists
- 69 Actors
- 3 Actresses
- 1 Actualities
- 1 Aculeo, Lake
- 1 Ad. Hache & Pepin Lehalleur Bros.
- 1 Adair & Co.
- 1 Adaire & Mullica Lumber Yard
- 1 Adalbert Hawsky (Firm)
- 24 Adam (Biblical figure)
- 2 Adam Exton & Co.
- 1 Adams' Brooms
- 5 Adams Express Company (Firm)
- 4 Adams Street
- 1 Adams, H. G. (Henry Gardiner), 1811 or 12-1881
- 5 Adams, John Quincy, 1767 - 1848
- 1 Adams, John,--1735-1826
- 1 Adams, W. Irving
- 1 Adamson see Baeder, Adamson
- 1 Adamson, William Clearfield Chemical Works
- 125 Adaptive reuse
- 2 Addams, Jane, 1860-1935
- 1 Addison Street
- 9 Additions (general components)
- 1 Adelphi Building
- 1 Adelphi Coach Works
- 1 Adelphi Theatre (London, England)
- 4 Adelphi Theatre, London
- 1 Adjournment
- 1 Adler, Cyrus, 1863-1940.
- 4 Administration
- 2 Admirals
- 1 Adolf Meyr's Nephew
- 1 Adolf Zsigmondy (Firm)
