Hesse-Nassau , a province of Prussia, consisting of the former electorate of Hesse-Cassel, the former duchy of Nassau, and the former free city of Frankfort, all of which were annexed to Prussia in 1866, and a few small districts which were ceded by Bavaria and the grand duchy of Hesse. It is bounded by the provinces of the Rhine, Westphalia, Hanover, and Saxony, by Waldeck, Brunswick, the Thuringian states, the grand duchy of Hesse, and Bavaria; area, 6,021 sq. m.; pop. in 1871, 1,400,370, of whom 491,933 were Protestants, 371,736 Roman Catholics, and 36,-390 Jews. It is divided into the districts of Cassel and Wiesbaden. The chief towns are Frankfort, Cassel, Marburg, Fulda, and Wies-baden. The principal rivers are the Main, with its affluent the Kinzig, the Rhine, on the western and southern frontiers, with the Lahn, and the Weser with the Fulda. The surface is mainly mountainous, the chief mountains being the Spessart, Rhon, Westerwald, Taunus, and offshoots of the Vogelgebirge, but it nowhere exceeds a height of 3,000 ft. Prominent among the productions are wine and wood; agriculture and cattle raising are extensively carried on. Among the manufactures, those of cloth, jewelry, iron, and pottery are the most flourishing.

The province is noted for the large number of its watering places, the best known of which are Ems, Soden, Wiesbaden, Schlangenbad, and Schwalbach. The province was formed in December, 1868. (See Hesse-Cassel, Nassau, and Frankfort.)