THE DELAWARE COUNTY LAND BRIEF
Land in the
Piedmont Uplands setting.
Delaware County has 183.8 square miles of land in Pennsylvania. 2 mapped landscape regions meet across Delaware County: Piedmont Uplands, Delaware River Terraces and Uplands.
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
Delaware County intersects 2 mapped regional units. The largest mapped shares are:
- Piedmont Uplands86.1%
- Delaware River Terraces and Uplands13.9%
Middle Atlantic Coastal Plain in Delaware County
Low coastal plains contain terraces, estuaries, marshes and barrier islands. Unconsolidated sediments underlie this varied coastal setting, with forest patterns changing near streams and low-lying areas.
Read the regional source ↗Finding your parcel within Delaware County
The atlas lists 67 cities, towns, townships, and Census communities associated with Delaware County, including Radnor, Concord, Middletown. The list includes overlapping geography types and does not divide the county into exclusive service areas.
Delaware County by land and water
The Census records 6.79 square miles of water within Delaware County, or 3.6% of its total area. That share is close to Delaware County’s 3.6%. This is geographic context; waterfront status and usable land must be checked at the parcel.
For scale, Delaware County has 240.9 times the land area of nearby Media borough (0.76 square miles). These areas describe boundaries, not comparable property prices.
The Census boundary meets Chester County, Montgomery County, Philadelphia County within Pennsylvania. A tract near one of these lines should be matched to the county identifier on its own records.

