pokelogan

pokelogan \POHK-loh-guhn\, noun:

Northeastern U.S. marshy or stagnant water that has branched off from a stream or lake.

They were particularly numerous where there was a small bay, or pokelogan, as it is called, bordered by a strip of meadow, or separated from the river by a low peninsula covered with coarse grass...
-- Henry David Thoreau, The Maine Woods, 1864

He weighted their bodies into the black stagnant water of a marshy pokelogan and watched them sink below the surface, being the last man to ever see them alive or dead.
-- Robert Olmstead, Soft Water, 1988

Pokelogan entered English in the 1840s and is of unknown origin.