The Isle au Haut 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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Isle au Haut’s center stands about 50 ft above sea level. Within three miles the land runs from 0 ft to 480 ft, a difference of 480 ft: hilly country. Open water lies within three miles. The highest named summit within 15 miles is Mount Chaplain, about 550 ft, 1 miles east-southeast.
Under the town center the state geologic map shows Devonian granite, from the Devonian, 359 to 422 million years old.
The section below crosses 2 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 59×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Granite. Age: Devonian, 359 to 422 million years old. About 8 mi of the line.
Gabbro, diorite, ultramafic. Age: Devonian, 359 to 422 million years old. About 0.4 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.
Rain that falls on Isle au Haut runs straight into the Atlantic Ocean.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Isle au Haut; river miles along the main stem, rounded.
