The Penn 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
77° on Nov. 15, 1993, the hottest reading for this week of the year since 1948. Next is 74° in 1989.
Penn’s center stands about 510 ft above sea level. Within three miles the land runs from 400 ft to 650 ft, a difference of 250 ft: rolling country. The highest named summit within 15 miles is Eagle Peak, about 1,320 ft, 14 miles northeast.
Under the town center the state geologic map shows Cocalico Formation (shale, siltstone), from the Ordovician, 445 to 487 million years old.
The section below crosses 17 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 22×. 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, siltstone. Age: Ordovician, 445 to 487 million years old. About 4 mi of the line.
Limestone. Age: Cambrian to Ordovician, 445 to 542 million years old. About 3 mi of the line.
Sandstone. Age: Triassic, 202 to 252 million years old. About 3 mi of the line.
Limestone, dolostone. Age: Ordovician, 445 to 487 million years old. About 3 mi of the line.
Limestone. Age: Ordovician, 445 to 487 million years old. About 2 mi of the line.
Limestone, dolostone. Age: Cambrian, 487 to 542 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. 11 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 Penn reaches Chesapeake Bay and the Atlantic Ocean by way of Chiques Creek and the Susquehanna: about 70 river miles.
Lake on the way: Lake Aldred.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Penn; river miles along the main stem, rounded.
Penn has a hot-summer humid continental climate. Summer afternoons average 87° in July; winter nights fall to about 22° in January. A normal year brings about 21 inches of snow; with the rain, that comes to about 44 inches of water.
On November 14 Penn normally reaches 55° and falls to 34°. The record high is 74°, in 1989; the record low 14°, in 1986. The most rain on this date, 1.57 in, fell in 1995.
Normals 1991–2020 and records since 1948 at Lancaster 2 NE Filt Plant, 11 miles south-southeast, 240 ft lower. NOAA, through RCC-ACIS.
