- Allington & Curtis Mfg. Co.1
- Allyn & Blanchard1
- Allyn House1
- Allyn, Blanchard & Latimer1
- Almar Construction Corp.1
- Alna Realty Corp.1
- Alpark Realty Corp.1
- Alsam Realty Corp.1
- Alson Co.4
- Alson Trading Co.1
- Aluminum Novelty Works1
- Alumni Federation of Columbia University1
- Amalgamated Clothing Workers of America1
- Ambrose E. Barnes & Bro.1
- American Academy in Rome1
- American Bank Note Company1
- American Card Clothing Co.1
- American Copper Brass & Iron Works1
- American Federation of Labor1
- American Glass Company1
- American Grocery Company4
- American Mills1
- American Nationalist (Organization)1
- American Novelty Cloak Co.1
- American ORT Federation1
- American Playhouse Theatrical Films1
- American Rubber Co.2
- American Supply Co.1
- American Surety Company4
- American Tube & Stamping Co.1
- American Wholesale Corporation1
- Amherst College. Library4
- Amor Building Corp.1
- Ampir Realty Corp.1
- Anderson & Krum Stationery Co.2
- Anderson, Sargent & Co.1
- Andrew Dutton1
- Andrew J. Joyce, Carriage Manufacturer1
- Anglo-Swiss Condensed Milk Company1
- Annal Co.1
- Anru Realty Corp.1
- Ansie Realty Corp.1
- Anthony Campagna and Sons12
- Anthony Properties, Inc.1
- Antoni Tadross & Co.1
- Apollo Theatre (Organization : New York, N.Y.)1
- Appel, Henry J.2
- Arbeit, Arnold A.9
- Arbuckle Bros.3
- Arbuckles & Co.1
- Arbuthnot, Stephenson & Co.1
- Architects Design Group3
- Architects and Engineers Affiliates1
- Archives internationales de la danse1
- Ardale Building Corp.1
- Ardlan Construction Co., Inc.1
- Argus Company1
- Arkell Weekly Co.1
- Armory Estates, Ltd.5
- Armstrong, Lorenzo D.1