The Guilford 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.
77° on Nov. 15, 1973, the hottest reading for this week of the year since 1910. Next is 75° in 1993.
Guilford’s center stands about 790 ft above sea level. Within three miles the land runs from 640 ft to 860 ft, a difference of 220 ft: rolling country. The highest named summit within 15 miles is Clarks Knob, about 2,340 ft, 12 miles northwest.
Under the town center the state geologic map shows Elbrook Formation (limestone), from the Cambrian, 487 to 542 million years old.
The section below crosses 13 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 13×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Quartzite. Age: Cambrian, 487 to 542 million years old. About 6 mi of the line.
Shale. Age: Ordovician, 445 to 487 million years old. About 4 mi of the line.
Limestone. Age: Cambrian, 487 to 542 million years old. About 3 mi of the line.
Limestone. Age: Ordovician, 445 to 487 million years old. About 2 mi of the line.
Quartzite. Age: Cambrian, 487 to 542 million years old. About 2 mi of the line.
Graywacke. Age: Ordovician, 445 to 487 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. 7 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 Guilford reaches Chesapeake Bay and the Atlantic Ocean by way of Falling Spring Branch, Conococheague Creek and the Potomac: about 270 river miles.
210 miles of the trip are on the Potomac.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Guilford; river miles along the main stem, rounded.
Guilford has a hot-summer humid continental climate. Summer afternoons average 88° in July; winter nights fall to about 22° in January. A normal year brings about 34 inches of snow; with the rain, that comes to about 42 inches of water.
On November 14 Guilford normally reaches 54° and falls to 34°. The record high is 73°, in 1989; the record low 14°, in 1986. The most rain on this date, 1.88 in, fell in 1995.
Normals 1991–2020 and records since 1910 at Shippensburg, 11 miles north-northeast, 110 ft lower. NOAA, through RCC-ACIS.