1916 Army Corps of Engineers maps

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1916 Army Corps of Engineers maps

April 23, 2011 by Laura Cooskey

I found these maps at the Humboldt County Department of Natural Resources, a division of the Public Works Dept., at 2nd and L Streets in Eureka. Years ago i had been in there and had some of the downriver maps photocopied; since then John Isom has given us the remaining Mattole sections. I am grateful to the staff at the DNR for allowing me to copy these materials.

Sections of four maps are presented here: the Cape Mendocino, Glynn, Pt. Delgada, and Briceland quadrangles. There is a lot of detail, and unfortunately, the file sizes are unwieldy. Still, if you blow them up too much, they will be pixelly. I tried to find a compromise. If you would personally like a better-resolution copy of any particular section, please ask me and i will email it to you.

These Corps of Engineers maps, made from surveys done in 1916 and printed by “Engineer Reproduction Plant, U.S. Army, Fort Humphreys, D.C., 1921,” don’t use the same township-and-range, 36-square-mile-block system as the other historical maps here. They are on a scale of 1/62,500. Since we can’t rely on your computer screen to represent inches fairly, please understand that one of the smaller, darker-lined squares measures about 2 and 7/8 miles, or 5000 yards, across. Unfortunately, those squares are only outlined on the Briceland and Cape Mendocino quadrangles, which also show the larger 5-minute (a minute being a 60th of a degree) squares. These big 5-minute boxes measure about 4 and ½ miles across and are represented by the only lines on the Glynn and Pt. Delgada maps.

On the original, an inch=a mile, so if you can adjust the size of your image until the smaller boxes are 2 and 7/8 true inches wide, and the larger, lightly-lined squares 4 and ½ inches, you can use that one-to-one scale: inches on your screen will equal miles.

As usual, the map sequence is NW progressing to the SE, upriver; then back to the Cooskie-King Range coast, north to south. Click on each image to enlarge it; click again for more magnification; and your own computer’s zoom function (usually control and +) will bring you in even further.