The Mount Holly Springs 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.
Mount Holly Springs’s center stands about 560 ft above sea level. Within three miles the land runs from 490 ft to 1,440 ft, a difference of 950 ft: steep hill country. The highest named summit within 15 miles is Lewis Rocks, about 1,710 ft, 12 miles southwest.
Under the town center the state geologic map shows Tomstown Formation (dolostone), from the Cambrian, 487 to 542 million years old.
The section below crosses 11 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 17×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Dolostone. Age: Cambrian, 487 to 542 million years old. About 5 mi of the line.
Limestone. Age: Ordovician, 445 to 487 million years old. About 4 mi of the line.
Quartzite. Age: Cambrian, 487 to 542 million years old. About 3 mi of the line.
Limestone. Age: Cambrian, 487 to 542 million years old. About 3 mi of the line.
Age: Precambrian. About 3 mi of the line.
Quartzite. 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. 5 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 Mount Holly Springs reaches Chesapeake Bay and the Atlantic Ocean by way of Mountain Creek, Yellow Breeches Creek and the Susquehanna: about 110 river miles.
Lake on the way: Lake Aldred.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Mount Holly Springs; river miles along the main stem, rounded.
Mount Holly Springs 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, 7 miles north, 130 ft lower. NOAA, through RCC-ACIS.
