List of tunnels documented by the Historic American Engineering Record in Maryland
# List of tunnels documented by the Historic American Engineering Record in Maryland

This is a list of tunnels documented by the Historic American Engineering Record in the U.S. state of Maryland.

## Tunnels

| Survey No. | Name (as assigned by HAER) | Built | Documented | Carries | Crosses | Location | County | Coordinates |
| - | - | - | - | - | - | - | - | - |
| MD-11 | Baltimore & Ohio Railroad, Howard Street Tunnel | 1895 | 1984 | CSX Baltimore Terminal Subdivision | Howard Street | Baltimore | Independent city | 39°18′17″N 76°37′15″W﻿ / ﻿39.30472°N 76.62083°W﻿ / 39.30472; -76.62083﻿ (Baltimore & Ohio Railroad, Howard Street Tunnel) |
| MD-15 | Baltimore & Ohio Railroad, Point of Rocks Tunnel | | 1971 | CSX Old Main Line Subdivision | Catoctin Mountain | Point of Rocks | Frederick | 39°16′30″N 77°32′39″W﻿ / ﻿39.27500°N 77.54417°W﻿ / 39.27500; -77.54417﻿ (Baltimore & Ohio Railroad, Point of Rocks Tunnel) |
| MD-17 | Baltimore & Ohio Railroad, Harpers Ferry Tunnel | 1894 | 1970 | Former Baltimore and Ohio Railroad | Elk Ridge | Maryland Heights | Washington | 39°19′27″N 77°43′26″W﻿ / ﻿39.32417°N 77.72389°W﻿ / 39.32417; -77.72389﻿ (Baltimore & Ohio Railroad, Harpers Ferry Tunnel) |
| MD-21 | Baltimore & Ohio Railroad, Ilchester Tunnel | 1903 | 1971 | Former Baltimore and Ohio Railroad | | Ilchester | Howard | 39°15′00″N 76°45′44″W﻿ / ﻿39.25000°N 76.76222°W﻿ / 39.25000; -76.76222﻿ (Baltimore & Ohio Railroad, Ilchester Tunnel) |
