- Lambertville Rubber Co.1
- Land Title and Trust Company1
- Landers, Frary & Clark1
- Lane Manufacturing Company2
- Langfeld Bros. & Co.2
- Langner & Kinnius1
- Lanphear & Haff1
- Larkin Co.1
- Larkin Soap Company2
- Larkin Soap M'f'g Co.4
- Lathrop, Ludington & Co.2
- Lautz Bro's & Co.1
- Lee & Bothwell1
- Lee Broom & Duster Co.1
- Lee-Coit-Andreesen Hardware Co.1
- Leeds & Hazard1
- Lehigh and New England Terminal Ware House Company1
- Leland House and Restaurant1
- Leon Levi, Jeweler1
- Lewis Coleman & Co.1
- Lewis DeGroff & Son Wholesale Grocers2
- Lewis and Clark County1
- Lidgerwood Manufacturing Company1
- Lincoln & Co.1
- Lindell1
- Litchfield Shuttle Co.1
- Little & Co.1
- Livingston1
- Livingston & Co.1
- Lloyd's Plate Glass Insurance Co.1
- Lockhart & Powers Picture Frame Moulding Works1
- Longmont Farmers Milling and Elevator Co.1
- Longstreth & Brother1
- Loring, Short & Harmon2
- Los Angeles Chamber of Commerce2
- Los Angeles Company1
- Los Angeles County (Calif.). Board of Supervisors1
- Loubat Glassware & Cork Co.1
- Louis F. Dow Co.1
- Louis Stern Sons, Inc.1
- Louisville Chemical Works1
- Louisville Lithographic Co.1
- Louisville Tin and Stove Company1
- Louisville Varnish Co.1
- Louisville and Old Inn Hotel1
- Ludlow Valve Manufacturing Co.3
- Lummis & Company1
- Lummus Cotton Gin Co.2
- Luther Keller2
- Lyford & Woodward1
- M. & H. Schrenkeisen2
- M. D. Wells Co.1
- M. E. Smith & Co.1
- M. Halstead & Co.1
- M. J. Earl1
- M. M. French & Co.1
- M. Oppenheimer & Co.2
- M. P. Moller1
- M. Ward. Close & Co.1
- M.J. Connell Company1