THE ADAMS COUNTY LAND BRIEF
Land in the
Triassic Lowlands setting.
Adams County has 518.6 square miles of land in Pennsylvania. 6 mapped landscape regions meet across Adams County: Triassic Lowlands, Northern Igneous Ridges, Trap Rock and Conglomerate Uplands, among others.
Rounded low hills, open valleys and irregular plains form a transition between Appalachian highlands and the coastal plain. The underlying geology mixes metamorphic, igneous and sedimentary rocks.
Regional context: Northern Piedmont ↗ · Regional mapping across the county footprint
Where the landscape changes
Adams County intersects 6 mapped regional units. The largest mapped shares are:
- Triassic Lowlands47%
- Northern Igneous Ridges24.2%
- Trap Rock and Conglomerate Uplands14.8%
- Northern Sedimentary and Metasedimentary Ridges6.2%
- Piedmont Limestone/Dolomite Lowlands4.8%
Blue Ridge in Adams County
Forested ridges, plateaus and high mountains extend through the Blue Ridge. Elevation, rainfall and sheltered coves create marked differences in forest communities across short distances.
Read the regional source ↗Finding your parcel within Adams County
The atlas lists 47 cities, towns, townships, and Census communities associated with Adams County, including Franklin, Menallen, Hamiltonban. The list includes overlapping geography types and does not divide the county into exclusive service areas.
Adams County by land and water
The Census records 3.15 square miles of water within Adams County, or 0.6% of its total area. That share is close to Adams County’s 0.6%. This is geographic context; waterfront status and usable land must be checked at the parcel.
For scale, Adams County has 15.1 times the land area of nearby Straban township (34.4 square miles). These areas describe boundaries, not comparable property prices.
The Census boundary meets Cumberland County, Franklin County, York County within Pennsylvania. A tract near one of these lines should be matched to the county identifier on its own records.

