The Lonerock 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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Lonerock’s center stands about 2,840 ft above sea level. Within three miles the land runs from 2,730 ft to 4,270 ft, a difference of 1,540 ft: steep hill country. The highest named summit within 15 miles is Opal Butte, about 5,010 ft, 14 miles east-southeast.
Under the town center the state geologic map shows John Day Formation of east-central Oregon (sandstone-mudstone), from the Late Eocene to Early Miocene, 16 to 38 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 7×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Basalt. Age: Early Miocene to Middle Miocene, 12 to 23 million years old. About 12 mi of the line.
Basalt. Age: Early Miocene to Middle Miocene, 12 to 23 million years old. About 5 mi of the line.
Sandstone-mudstone. Age: Late Eocene to Early Miocene, 16 to 38 million years old. About 3 mi of the line.
Andesite. Age: Paleocene to Early Oligocene, 28 to 66 million years old. About 3 mi of the line.
Coarse-detrital. Age: Pleistocene to Holocene, less than 2.6 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.
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 Lonerock reaches the Pacific Ocean by way of Lone Rock Creek, Rock Creek, the John Day and the Columbia: about 300 river miles.
Lake on the way: Lake Umatilla.
210 miles of the trip are on the Columbia.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Lonerock; river miles along the main stem, rounded.
