- Ajello, G.1
- Akiba Development Corp.1
- Akron Shoe Co.1
- Al-Shathry Consulting Engineers1
- Alabastine Company1
- Alan H. Polkes Associates, Inc.3
- Alaska Treadwell Gold Mining Co.1
- Albanese, Anthony A.1
- Albemarle Construction Corp.1
- Albemarle Gardens, Inc.2
- Alber Construction Corp.1
- Alberly Holding Corp.1
- Albert B. Ashforth, Inc.62
- Albert Glassman2
- Albert and Harrison, Inc.1
- Alberta Chair Works1
- Albini and Raddock2
- Albini, Louis V.6
- Albright, P. H1
- Alcor Realty Corp.4
- Alden Builders, Inc.1
- Alderton Co.2
- Alderton Hall, Inc.2
- Alexander Wolf and Co., Inc.58
- Alexander, Harry1
- Alfred Kaskel and Son4
- Alfred Munroe & Co.1
- Alfred S. Campbell Art Co.1
- Algin Management Co.1
- Algon Realty Corp.1
- All States Terminal Corp.3
- Allaire Works1
- Allan H. Feinberg Associates1
- Allen, Elsie, 1869-195162
- Allen, Henry Justin, 1868-195062
- Allen, Stan1
- Allen-Ditchett Company2
- Allentown Manufacturing Co.2
- Alley Park Housing Corp.2
- Allied Realties1
- Allin Bros3
- Allington & Curtis Mfg. Co.2
- Allou Associates1
- Allsteel, Inc.5
- Allyn & Blanchard1
- Allyn House1
- Allyn, Blanchard & Latimer1
- Alman & Co.5
- Almar Construction Corp.1
- Alna Realty Corp.1
- Alpark Realty Corp.1
- Alpern, Andrew1
- Alret Realty Corp.1
- Alsam Realty Corp.1
- Alson Co.4
- Alson Trading Co.1
- Althouse Bros. Real Estate1
- Aluminum Novelty Works1
- Alvord, Corydon A., approximately 1812-18741
- Amal Realty1