- 11 Lighting fixtures
- 1 Lighting industry
- 5 Lightning
- 14 Lilies (Lily)
- 2 Lillian Marrero Branch
- 1 Lillyvick, Mr (Fictitious character)
- 1 Lily Lake
- 1 Limbo
- 2 Lime kilns
- 1 Limeburner, Alexis J.
- 8 Limekiln Pike
- 1 Limerick, Pennsylvania
- 1 Limoges
- 4 Limoges, France
- 2 Lincoln Drive
- 2 Lincoln Mills
- 81 Lincoln, Abraham, 1809-1865
- 1 Lind, Jenny (1820-1887)
- 1 Lind, Jenny, 1820-1887
- 3 Lindbergh Boulevard
- 1 Lindbergh Kidnapping
- 3 Lindley Avenue
- 2 Line Lexington, Pennsylvania
- 1 Lineaweaver & Wallace Printers & Publishers
- 1 Linehan see Green & Linehan
- 7 Linen industry
- 5 Linens
- 2 Lines (geometric concept)
- 1 Lingham, Conway
- 1 Link Bros. Philadelphia Terra Cotta Works
- 2 Linley Street
- 11 Linocuts (prints)
- 4 Linoleum
- 4 Linoleum blocks
- 9 Linoleum-block printing
- 4 Linseed oil
- 2 Linwood, Pennsylvania
- 58 Lions
- 1 Lippen's Hotel
- 1 Lippincott, J. B. (Joshua Ballinger), 1813-1886