Pennsylvania - Criteria: C (architecture/engineering)
| Kurtz, T. M., House |
| Kutz Mill |
| Kutz's Mill Bridge |
| Kutztown 1892 Public School Building |
| La Blanche Apartments |
| Lacawac |
| Lacey, Gen. John, Homestead |
| Lackawanna Avenue Commercial Historic District |
| Lackawanna Iron and Coal Company Furnace |
| Lahr Farm |
| Lake City School |
| Lancaster Armory |
| Lancaster City Historic District |
| Lancaster County Courthouse |
| Lancaster County House of Employment |
| Lancaster Crematorium |
| Lancaster Historic District |
| Lancaster Trust Company |
| Lancaster Watch Company |
| Landis Homestead |
| Landis Mill Covered Bridge |
| Landreth, David, School |
| Land Title Building |
| Lane House |
| Langhorne Historic District |
| Langhorne Library |
| Langhorne Manor School |
| Langley High School |
| Lansdowne Park Historic District |
| Lansdowne Theatre |
| Lapp Log House |
| Larimer School |
| Larkin-Belber Building |
| Larkin Covered Bridge |
| Latimer School |
| Latrobe Armory |
| Laughlin, Hugh, House |
| Laurel Hill Cemetery |
| Laurel Hill RDA |
| Laurel-Rex Fire Company House |
| Lawrence County Courthouse |
| Lawrence Public School |
| Layton Bridge |
| Lazaretto, The |
| Lea, Henry C., School of Practice |
| Leaman Place Covered Bridge |
| Leap-the-Dips |
| Leas, Benjamin B., House |
| Leaser, Frederick and Catherine, Farm |
| Leedom, David, Farm |
| Legislative Route 1 Sycamore Allee |
| Lehigh Canal |
| Lehigh Valley Railroad Headquarters Building |
| Lehigh Valley Silk Mills |
| Lehner Grain-and-Cider Mill and House |
| Leiby, Jacob, Farm |
| Leidy, Dr. Joseph, House |
| Leiper, Thomas, Estate |
| Lemington Elementary School |
| Lemont Historic District |
| LeMoyne Crematory |
| Lenape Bridge |
| Lenhart Farm |
| Lerch Tavern |
| Letsche Elementary School |
| Levering, William, School |
| Lewisburg Armory |
| Lewisburg Historic District |
| Lewis, Evan, House |
| Lewistown Armory |
| Liberty Bridge |
| Liberty Fire Company No. 5 |
| Liberty Hall |
| Liberty School No. 4, Friendship Building |
| Lightfoot Mill |
| Lightner, Isaac, House |
| Ligonier Armory |
| Ligonier Historic District |
| Lilly Bridge |
| Lime Valley Covered Bridge |
| Lincoln Elementary School |
| Lincoln, Mordecai, House |
| Lindbergh Viaduct |
| Linden Avenue School |
| Linden Grove Pavilion |
| Linden Hall at Saint James Park |
| Linden Hall Historic District |
| Linden House |
| Lindsey, Christiana, House |
| Linn Run State Park Family Cabin District |
| Lititz Moravian Historic District |
| Lits Department Store |
| Littell, David, House |
| Little Buffalo Historic District |
| Little Gap Covered Bridge |
| Little, Moses, Tavern |
| Livingood House-Stryker Hospital |
| Lloyd and Henry Warehouse |
| Llyswen Historic District |
| Lochiel Farm |
Data from United States Park Service and Wikidata
