Hanau , a town of Prussia, in the province of Hesse-Nassau, at the junction of the Main and the Kinzig, 10 m. E. of Frankfort; pop. in 1871, 20,278. It contains an ancient castle, now the seat of the Wetteravian society of natural history, one Catholic and three Protestant churches, an academy of design, and several schools. There are manufactories of silks, cottons, carpets, leather, iron ware, pottery, and jewelry, and a large trade in woods, drugs, and dyes. In the vicinity are the mineral baths of Wilhelmsbad. Here, on Oct. 30, 1813, Napoleon, on his retreat from Leipsic, defeated the Germans under Marshal Wrede. During the middle ages it was the capital of the sovereign counts of Hanau. In 1451 the county was divided into two states, Hanau-Munzenberg and Hanau-Lichtenberg, the rulers of both of which were made princes in 1696. In 1736 the house of Hanau became extinct, when Hanau-Munzenberg was united with the electorate of Hesse-Cassel, and Hanau-Lichtenberg with Hesse-Darmstadt; but in 1785 this division too was incorporated in the electorate.

As a part of the latter Hanau was annexed to Prussia in 1866.