Benson Lossing describes the overslagh near Castleton in 1866:
" In this vicinity is the famous hidden sand-bar, called Overslagh by the Dutch, so formidable by navigators of this part of the river, not because of any actual danger, but of tedious detentions caused by running aground.. Some improvements have been made. In former years the sight of from twenty to fifty sail of river craft, fast aground on the Overslagh at low tide, was not rare, and the amount of profanity uttered by the vexed sailors was sufficient to demoralize the whole district. This bar is formed by the sand brought in by the Norman's Kill and other streams, and large sums have been expended in damming, dredging, and dyking, without entire success. As early as 1790, the State legislature authorized the proprietors of Mills and Papskni Islands to erect a dam or dyke between them, so as to throw all the water into the main channel, and thus increase its velocity sufficient to carry away the accumulating sand. It abated, but did not cure the difficulty. This bar is a perpetual contradiction to the frequent boast, that the navigation of the Hudson is unobstructed along its entire tide-watercourse. The Overslagh is the only exception, however.
Arthur Adams in The Hudson River Guidebook explains that the accumulation of sand continued to be a problem and that there were more dredging projects in later years. In 1954, the channel was dredged to 32 feet and then later it was deepened to 34 feet deep.