Hesse (Hes'seh; Ger. Hessen), or Hesse-Darmstadt, a German grand-duchy, divided by a strip of Hesse-Nassau into a northern part, Ober-hessen, completely enclosed by Prussia, and a southern part, comprising Starkenburg, east of the Rhine, and Rheinhessen, west of the Rhine.

Besides, there are eleven enclaves in Baden and Prussia. Oberhessen is partly occupied in the east by the Vogelsberg, culminating in Tauf-stein (2532 feet), in the south-west by a ramification of the Taunus, the fertile and undulating valley of Wetterau lying between them. Starkenburg, in the south-east, is covered by part of the Odenwald. The Bergstrasse divides the uplands of Starkenburg from the plain of the Rhine. Rheinhessen, fertile and populous uplands, laid out largely in vineyards, lies between Kreuz-nach, Mainz, and Worms. Except some streams draining into the Fulda and Weser, the waters of Hesse - Main, Neckar, and Lahn - belong to the Rhine system. Of the total surface, com-prising 2966 sq. m., 50 per cent. is tilled land and garden, and 31 forest. The most important products are corn, pulse, potatoes, rape, poppy, tobacco, flax, fruit, vines, iron, manganese ore, and peat. The industries - mainly in Mainz, Offenbach, and Worms - include the making of leather, boots, upholstery, tobacco, cigars, chemicals, etc. The total pop. amounted in 1875 to 882,349, in 1900 to 1,119,893. Of these 489,512 belonged to Starkenburg, and 746,201 were Protestants. The chief towns are Mainz, Darmstadt (the capital), Offenbach, Worms, and Giessen. The Hessians were an ancient German tribe in Thuringia ; but we first hear of the landgrave of Hesse in the 13th century. In 1806 Louis X. assumed the title of grand-duke. In 1866 Hesse, having sided with Austria, had to yield up Hesse-Homburg, etc, to Prussia.