The Big Sky Colony 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 sunny
Mostly sunny; warmer
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Chance of showers; cooler
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Mostly cloudy
Big Sky Colony’s center stands about 4,260 ft above sea level. Within three miles the land runs from 4,060 ft to 4,570 ft, a difference of 510 ft: hilly country. The highest named summit within 15 miles is Twin Buttes, about 4,900 ft, 12 miles west-northwest.
Under the town center the state geologic map shows Horsethief Formation (sandstone), from the Late Cretaceous, 66 to 72 million years old.
The section below crosses 5 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 23×. 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. Age: Late Cretaceous, 72 to 84 million years old. About 6 mi of the line.
Mudstone, sandstone. Age: Late Cretaceous to Early Paleocene, 62 to 72 million years old. About 6 mi of the line.
Shale, siltstone, sandstone. Age: Late Cretaceous, 66 to 72 million years old. About 5 mi of the line.
Sandstone, siltstone, mudstone. Age: Late Cretaceous, 66 to 84 million years old. About 5 mi of the line.
Sandstone. Age: Late Cretaceous, 66 to 72 million years old. About 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 Big Sky Colony reaches the Gulf of America by way of Cut Bank Creek, the Marias, the Missouri and the Mississippi: about 3,440 river miles.
Lakes on the way: Lake Oahe, Lake Sakakawea, Lake Fort Peck and Lake Sharpe.
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 Big Sky Colony; river miles along the main stem, rounded.
