The West Pennsboro plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
Mostly cloudy
Partly cloudy; warmer
Partly cloudy
Sunny
Sunny
Mostly sunny
Mostly sunny
76° on Nov. 11, 2020, the hottest reading for this week of the year since 1840. Next is 74° in 2009.
West Pennsboro’s center stands about 500 ft above sea level. Within three miles the land runs from 450 ft to 690 ft, a difference of 240 ft: rolling country. The highest named summit within 15 miles is Fenton Knob, about 2,210 ft, 15 miles west-northwest.
Under the town center the state geologic map shows St. Paul Group (limestone), from the Ordovician, 445 to 487 million years old.
The section below crosses 16 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 12×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Shale. Age: Ordovician, 445 to 487 million years old. About 6 mi of the line.
Quartzite. Age: Cambrian, 487 to 542 million years old. About 3 mi of the line.
Dolostone. Age: Cambrian, 487 to 542 million years old. About 3 mi of the line.
Limestone. Age: Cambrian, 487 to 542 million years old. About 2 mi of the line.
Limestone. Age: Ordovician, 445 to 487 million years old. About 2 mi of the line.
Shale, sandstone. Age: Silurian, 422 to 445 million years old. About 2 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale. 10 smaller units along the line are not listed.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
A raindrop that lands in West Pennsboro reaches Chesapeake Bay and the Atlantic Ocean by way of West Branch Mount Rock Spring Creek, Conodoguinet Creek and the Susquehanna: about 130 river miles.
Lake on the way: Lake Aldred.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of West Pennsboro; river miles along the main stem, rounded.
West Pennsboro has a hot-summer humid continental climate. Summer afternoons average 86° in July; winter nights fall to about 21° in January. A normal year brings about 28 inches of snow; with the rain, that comes to about 48 inches of water.
Normals 1991–2020 and records since 1840 at Carlisle Water Plant, 8 miles east-northeast. NOAA, through RCC-ACIS.
