The Rushmore 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.
79° on Nov. 14, 1999, the hottest reading for this week of the year since 1971. Next is 72° in 2001.
Rushmore’s center stands about 1,670 ft above sea level. Within three miles the land runs from 1,580 ft to 1,690 ft, a difference of 110 ft: gently rolling country.
Under the town center the state geologic map shows Undifferentiated (conglomerate, sandstone, mudstone), from the Late Cretaceous, 72 to 100 million years old.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 64×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Conglomerate, sandstone, mudstone. Age: Late Cretaceous, 72 to 100 million years old. About 24 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
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 Rushmore reaches the Gulf of America by way of Little Rock Creek, the Little Rock, the Rock River, the Big Sioux, the Missouri and the Mississippi: about 2,060 river miles.
1,170 miles of the trip are on the Mississippi.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Rushmore; river miles along the main stem, rounded.
Rushmore has a warm-summer humid continental climate. Summer afternoons average 82° in July; winter nights fall to about 5° in January. A normal year brings about 45 inches of snow; with the rain, that comes to about 30 inches of water.
On November 14 Rushmore normally reaches 42° and falls to 24°. The record high is 79°, in 1999; the record low −4°, in 1986. The most rain on this date, 0.30 in, fell in 2024.
Normals 1991–2020 and records since 1971 at Worthington 2 NNE, 11 miles east, 100 ft lower. NOAA, through RCC-ACIS.