EMS, the ancient Amisus, a river in the N.W. of Germany, rising in the Teutoburg forest, Westphalia, S.W. of Detmold. It flows first westward through the Prussian territory, and afterwards takes a northern direction through Hanover, to the Dollart, a gulf of the North Sea between Holland and Hanover. It has an entire course of about 160 miles, and is navigable for vessels of 80 or 100 tons as far as Passenburg. The principal tributaries are the An, the Haase, and the Leda, which fall into it from the right.