The McCammon 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.
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66° on Nov. 15, 2025, the hottest reading for this week of the year since 1895. Next is 65° in 2016.
McCammon’s center stands about 4,760 ft above sea level. Within three miles the land runs from 4,590 ft to 5,870 ft, a difference of 1,280 ft: steep hill country. The highest named summit within 15 miles is Bonneville Peak, about 9,250 ft, 8 miles north-northeast.
Under the town center the state geologic map shows Basalt (Pleistocene and Pliocene), from the Late Pliocene to Pleistocene, less than 3 million years old.
The section below crosses 6 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 5×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Silt. Age: Pleistocene, less than 2.6 million years old. About 11 mi of the line.
Age: Neoproterozoic to Cambrian, 487 to 1,000 million years old. About 4 mi of the line.
Basalt. Age: Late Pliocene to Pleistocene, less than 3 million years old. About 4 mi of the line.
Mixed-clastic, volcanic. Age: Early Miocene to Pleistocene, 2 to 16 million years old. About 3 mi of the line.
Limestone, dolostone. Age: Cambrian to Ordovician, 445 to 542 million years old. About 2 mi of the line.
Gravel, sand, silt. Age: Quaternary, less than 2.6 million years old. About 0.3 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 McCammon reaches the Pacific Ocean by way of the Portneuf, the Snake and the Columbia: about 1,100 river miles.
Lakes on the way: American Falls Reservoir, Lake Umatilla, Brownlee Reservoir and Cove Arm Lake.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of McCammon; river miles along the main stem, rounded.
McCammon has a warm-summer humid continental climate. Summer afternoons average 89° in July; winter nights fall to about 14° in January. About 16 inches of rain fall in a normal year.
Normals 1991–2020 and records since 1895 at Downey, 16 miles south-southeast, 100 ft higher. NOAA, through RCC-ACIS.
