Feature Name | Class | Elev. meters | County | Latitude DMS | Longitude DMS |
| Havenwood Hills | Populated Place | 213 | Washington | 39 38 30 N | 077 35 51 W |
| Hawkins Zouaves Monument | Park | 152 | Washington | 39 27 09 N | 077 44 36 W |
| Hawks Hill | Summit | 287 | Washington | 39 24 04 N | 077 42 30 W |
| Hearthstone Mountain | Summit | 616 | Washington | 39 42 43 N | 077 58 20 W |
| Hellane Park | Park | 196 | Washington | 39 39 04 N | 077 44 26 W |
| Heritage Academy | School | 125 | Washington | 39 39 00 N | 077 49 43 W |
| Heritage Estates | Populated Place | 146 | Washington | 39 33 02 N | 077 45 34 W |
| Hickory Elementary School | School | 159 | Washington | 39 37 08 N | 077 46 35 W |
| Hicks Bridge | Bridge | 103 | Washington | 39 29 16 N | 077 42 50 W |
| High Germany | Bend | 127 | Washington | 39 37 36 N | 077 49 30 W |
| High Rock | Summit | 559 | Washington | 39 41 42 N | 077 31 21 W |
| Highfield | Populated Place | 426 | Washington | 39 43 05 N | 077 28 52 W |
| Highfield Cascade | Populated Place | 425 | Washington | 39 43 02 N | 077 29 24 W |
| Highfield Post Office | Post Office | 430 | Washington | 39 43 05 N | 077 29 19 W |
| Highland View Academy | School | 193 | Washington | 39 35 34 N | 077 36 55 W |
| Hill Village | Populated Place | 171 | Washington | 39 42 25 N | 077 37 06 W |
| Hinkle Run | Stream | | Washington | 39 41 02 N | 077 58 26 W |
| Holiday Acres | Populated Place | 210 | Washington | 39 38 40 N | 077 36 09 W |
| Holiday Farms | Populated Place | 214 | Washington | 39 38 39 N | 077 36 27 W |
| Homewood Retirement Center | Building | 146 | Washington | 39 36 23 N | 077 47 51 W |
| Hopkins Ridge | Populated Place | 499 | Washington | 39 38 06 N | 077 32 39 W |
| Horse Shoe Bend | Populated Place | 133 | Washington | 39 26 19 N | 077 43 46 W |
| Horseshoe Bend | Bend | 114 | Washington | 39 26 15 N | 077 44 18 W |
| Horseshoe Bend | Bend | 119 | Washington | 39 28 36 N | 077 47 36 W |
| Horseshoe Bend Campground | Locale | 92 | Washington | 39 29 11 N | 077 46 35 W |
| House of Prayer for All People | Church | 164 | Washington | 39 38 11 N | 077 43 22 W |
| Howard School | School | 164 | Washington | 39 37 40 N | 077 43 40 W |
| Hunter Hill | Populated Place | 172 | Washington | 39 40 52 N | 077 41 07 W |
| Huyett | Populated Place | 146 | Washington | 39 39 05 N | 077 47 57 W |
| Huyettes Mennonite School | School | 152 | Washington | 39 39 07 N | 077 48 10 W |
| Hyde Park (subdivision) | Populated Place | 183 | Washington | 39 40 13 N | 077 43 39 W |
| Independence School (historical) | School | 155 | Washington | 39 40 28 N | 077 50 12 W |
| Indian Springs | Populated Place | 165 | Washington | 39 38 47 N | 078 00 06 W |
| Indian Springs | Spring | 368 | Washington | 39 39 59 N | 077 57 54 W |
| Indian Springs Run | Stream | | Washington | 39 40 00 N | 077 59 38 W |
| Indian Springs Wildlife Demonstration Area | Park | 418 | Washington | 39 42 14 N | 077 59 46 W |
| Indian Springs Wildlife Management Area | Park | 475 | Washington | 39 43 00 N | 078 00 00 W |
| Interchange 1 | Crossing | 152 | Washington | 39 42 50 N | 078 11 19 W |
| Interchange 1 | Crossing | 139 | Washington | 39 35 15 N | 077 49 00 W |
| Interchange 10 | Crossing | 201 | Washington | 39 42 02 N | 077 44 21 W |
| Interchange 12 | Crossing | 143 | Washington | 39 37 41 N | 078 00 59 W |
| Interchange 18 | Crossing | 170 | Washington | 39 39 06 N | 077 55 24 W |
| Interchange 2 | Crossing | 170 | Washington | 39 42 27 N | 078 11 01 W |
| Interchange 2 | Crossing | 134 | Washington | 39 36 20 N | 077 48 11 W |
| Interchange 24 | Crossing | 125 | Washington | 39 37 49 N | 077 48 34 W |
| Interchange 26 | Crossing | 152 | Washington | 39 37 01 N | 077 47 09 W |
| Interchange 29 | Crossing | 155 | Washington | 39 36 20 N | 077 43 44 W |
| Interchange 3 | Crossing | 145 | Washington | 39 41 45 N | 078 08 59 W |
| Interchange 32 | Crossing | 170 | Washington | 39 36 00 N | 077 40 58 W |
| Interchange 35 | Crossing | 158 | Washington | 39 35 09 N | 077 38 24 W |
| Interchange 4 | Crossing | 152 | Washington | 39 37 01 N | 077 47 09 W |
| Interchange 5 | Crossing | 144 | Washington | 39 41 27 N | 078 07 49 W |
| Interchange 6 | Crossing | 171 | Washington | 39 37 40 N | 077 46 29 W |
| Interchange 6 | Crossing | 180 | Washington | 39 39 11 N | 077 45 00 W |
| Interchange 7 | Crossing | 189 | Washington | 39 39 48 N | 077 44 24 W |
| Interchange 8 | Crossing | 195 | Washington | 39 40 06 N | 077 44 11 W |
| Interchange 9 | Crossing | 131 | Washington | 39 39 19 N | 078 03 04 W |
| Interchange 9 | Crossing | 201 | Washington | 39 41 22 N | 077 44 00 W |
| Interstate Industrial Park | Locale | 139 | Washington | 39 35 50 N | 077 48 15 W |
| Israel Creek | Stream | | Washington | 39 19 38 N | 077 40 54 W |
| James Rumsey Bridge | Bridge | 85 | Washington | 39 26 11 N | 077 48 05 W |
| Jamison Yard | Locale | 181 | Washington | 39 38 15 N | 077 45 18 W |
| Jefferson Heights | Populated Place | 170 | Washington | 39 38 38 N | 077 40 37 W |
| John Wesley United Methodist Church | Church | 171 | Washington | 39 38 38 N | 077 43 09 W |
| Johns Hopkins University Geological Research Station | School | 295 | Washington | 39 41 05 N | 077 58 39 W |
| Johnson Mountain | Summit | 348 | Washington | 39 40 30 N | 077 56 04 W |
| Jonathan Hager House and Museum | Building | 169 | Washington | 39 38 07 N | 077 43 56 W |
| Jones Chapel (historical) | Church | 151 | Washington | 39 38 02 N | 077 49 12 W |
| Jugtown | Populated Place | 234 | Washington | 39 36 45 N | 077 35 38 W |
| Keedysville | Populated Place | 120 | Washington | 39 29 10 N | 077 41 59 W |
| Keedysville Post Office | Post Office | 115 | Washington | 39 29 11 N | 077 42 03 W |
| Keedysville Spring | Spring | 119 | Washington | 39 29 15 N | 077 41 32 W |
| Kemp Horn Vocational Center | School | 286 | Washington | 39 38 37 N | 077 34 05 W |
| Kemps | Populated Place | 128 | Washington | 39 36 49 N | 077 48 48 W |
| Kenley Village Shopping Center | Locale | 158 | Washington | 39 37 17 N | 077 42 44 W |
| Kent Estates | Populated Place | 164 | Washington | 39 42 30 N | 077 46 08 W |
| Killiansburg Cave Campground | Locale | 94 | Washington | 39 27 26 N | 077 47 47 W |
| Kings Apostolic Church of God | Church | 171 | Washington | 39 38 49 N | 077 43 14 W |
| Kinsey Heights (subdivision) | Populated Place | 187 | Washington | 39 31 10 N | 077 38 59 W |
| Kirk Woods | Populated Place | 130 | Washington | 39 42 30 N | 078 11 58 W |
| Kline Mill | Populated Place | 142 | Washington | 39 33 02 N | 077 40 43 W |
| Knott Island | Island | 84 | Washington | 39 25 00 N | 077 44 57 W |
| Lake Edward Elliote Jenkins | Reservoir | 146 | Washington | 39 38 12 N | 078 18 17 W |
| Lake Fairplay Estates | Populated Place | 136 | Washington | 39 32 13 N | 077 46 16 W |
| Lake Jenkins | Reservoir | 147 | Washington | 39 38 14 N | 078 18 16 W |
| Lake Jenkins Dam | Dam | 147 | Washington | 39 38 14 N | 078 18 16 W |
| Lake Lanahan | Reservoir | 153 | Washington | 39 38 26 N | 078 18 11 W |
| Lake Lanahen Dam | Dam | 153 | Washington | 39 38 26 N | 078 18 11 W |
| Lake Nesbit and Lanhan | Reservoir | 162 | Washington | 39 38 24 N | 078 18 11 W |
| Lake Royer | Lake | 405 | Washington | 39 42 37 N | 077 29 45 W |
| Lake Royer | Reservoir | 403 | Washington | 39 42 42 N | 077 29 41 W |
| Landis Spring Branch | Stream | | Washington | 39 34 16 N | 077 41 21 W |
| Lanes Run | Stream | | Washington | 39 39 37 N | 078 02 23 W |
| Lappans | Populated Place | 140 | Washington | 39 33 13 N | 077 44 14 W |
| Lehmans Mill | Locale | 177 | Washington | 39 42 42 N | 077 40 30 W |
| Lehmans Mill Historic District | Park | 177 | Washington | 39 42 41 N | 077 40 34 W |
| Leitersburg | Populated Place | 181 | Washington | 39 41 33 N | 077 37 22 W |
| Leitersburg Volunteer Fire Company 9 | Building | | Washington | 40 09 33 N | 078 02 14 W |
| Lemons Ferry (historical) | Crossing | 97 | Washington | 39 35 57 N | 077 49 50 W |
| Licking Creek | Stream | | Washington | 39 39 02 N | 078 02 59 W |
| Licking Creek | Stream | 109 | Washington | 39 39 01 N | 078 03 04 W |
| Licking Creek Aqueduct | Bridge | 114 | Washington | 39 39 04 N | 078 02 55 W |
| Lincolnshire School | School | 183 | Washington | 39 37 02 N | 077 45 33 W |
| Little Antietam Creek | Stream | | Washington | 39 29 02 N | 077 42 57 W |
| Little Antietam Creek | Stream | | Washington | 39 40 56 N | 077 38 22 W |
| Little Antietam Medical Center | Hospital | 132 | Washington | 39 28 51 N | 077 42 10 W |
| Little Beaver Creek | Stream | | Washington | 39 32 45 N | 077 40 46 W |
| Little Conococheague Creek | Stream | | Washington | 39 36 13 N | 077 54 28 W |
| Little Cove Creek | Stream | | Washington | 39 43 17 N | 078 02 41 W |
| Little Metropolitan Cemetery | Cemetery | 177 | Washington | 39 39 08 N | 077 55 53 W |