Every NPS unit in Maryland.
Maryland's 27 NPS units: 6 Parks · 4 Others · 3 National Historic Trails · 3 National Historical Parks · 3 National Historic Sites · 2 National Battlefields · 2 National Scenic Trails · 1 National Seashore · 1 Parkway · 1 National Monument and Historic Shrine · 1 Memorial Parkway. Combined 5-year-average annual visits: 22,539,712 (multi-state units count their full visits in every state they touch — see methodology). The most-visited unit is George Washington Memorial Parkway at about 7.03M annual visits.
| Unit | Designation | 5-yr avg visits | Busiest month |
|---|---|---|---|
| George Washington Memorial Parkway | Memorial ParkwayGWMP | 7,025,042 | August |
| Appalachian National Scenic Trail | National Scenic TrailAPPA | 6,215,118 | July |
| Chesapeake & Ohio Canal National Historical Park | National Historical ParkCHOH | 4,552,595 | September |
| Assateague Island National Seashore | National SeashoreASIS | 2,392,510 | July |
| Fort Washington Park | ParkFOWA | 496,919 | July |
| Catoctin Mountain Park | ParkCATO | 448,938 | October |
| Harpers Ferry National Historical Park | National Historical ParkHAFE | 434,030 | October |
| Fort McHenry National Monument and Historic Shrine | National Monument and Historic ShrineFOMC | 296,240 | July |
| Piscataway Park | ParkPISC | 282,917 | July |
| Antietam National Battlefield | National BattlefieldANTI | 147,614 | September |
| Monocacy National Battlefield | National BattlefieldMONO | 125,986 | July |
| Greenbelt Park | ParkGREE | 76,887 | May |
| Hampton National Historic Site | National Historic SiteHAMP | 19,296 | May |
| Harriet Tubman Underground Railroad National Historical Park | National Historical ParkHATU | 14,913 | July |
| Clara Barton National Historic Site | National Historic SiteCLBA | 5,908 | August |
| Thomas Stone National Historic Site | National Historic SiteTHST | 4,799 | May |
| Baltimore-Washington Parkway | ParkwayBAWA | — | — |
| Captain John Smith Chesapeake National Historic Trail | National Historic TrailCAJO | — | — |
| Chesapeake Bay | —CBPO | — | — |
| Civil War Defenses of Washington | —CWDW | — | — |
| Fort Foote Park | ParkFOFO | — | — |
| Glen Echo Park | ParkGLEC | — | — |
| Harmony Hall | —HAHA | — | — |
| Oxon Cove Park & Oxon Hill Farm | —OXHI | — | — |
| Potomac Heritage National Scenic Trail | National Scenic TrailPOHE | — | — |
| Star-Spangled Banner National Historic Trail | National Historic TrailSTSP | — | — |
| Washington-Rochambeau Revolutionary Route National Historic Trail | National Historic TrailWARO | — | — |
Methodology
Unit list and per-unit visit counts come from the official NPS Visitor Use Statistics Data Package, 2025. The "5-year average visits" column is the mean of 2021-2025 Recreation Visits. Multi-state NPS units (Yellowstone, Death Valley, Great Smoky Mountains and others) are listed under every state they touch; the per-unit visit count is the unit's total, not a per-state share. Independent site, not affiliated with the National Park Service.
Independent site. Not affiliated with or endorsed by the National Park Service. Data comes from the official NPS Visitor Use Statistics Data Package, 2025; editorial analysis is ours. The NPS Arrowhead and other NPS marks are not used.