L
- L-plan buildings (99)
- labor housing (105)
- labor unions (7)
- laboratories (95)
- laborers (5)
- lakes (4)
- lampposts (1)
- landings (marine structures) (1)
- landscape architects (2)
- landscapes (7)
- lateral sewers (1)
- Latin cross buildings (8)
- latrines (5)
- launch complexes (24)
- launching ramps (2)
- launchings (8)
- laundries (11)
- laundry (16)
- law & legal affairs (12)
- law enforcement (63)
- law offices (7)
- leather industry (1)
- lecture halls (2)
- legislators (30)
- leisure (5)
- libraries (35)
- lifeboat stations (3)
- lifesaving stations (5)
- lift locks (17)
- light stations (26)
- lighthouses (27)
- lightships (1)
- lime kilns (8)
- limestone quarries (1)
- Lincoln Highway (8)
- liveries (2)
- livestock loading chutes (1)
- livestock (8)
- living rooms (1)
- loading docks (2)
- lock gates (3)
- locker rooms (5)
- lockkeepers' houses (14)
- locks (hydraulic facilities) (66)
- locomotive erecting shops (1)
- lodges (22)
- lodging houses (24)
- loft buildings (5)
- log buildings (210)
- log cabins (79)
- log joints (1)
- lumber industry (13)
- lumber (15)
- Lutheran churches (11)