Military Frontier (Ger. Militargrenze; Hung. Hatdror-videF), a region, and formerly a political division, of the Austro-Hungarian monarchy, between lat. 44° and 47° N., and Ion. 14° and 23° E., bounded N. by Carniola, Croatia, Slavonia, and Hungary, E. by Transylvania and Roumania, S. by Servia, Bosnia, and Dalmatia, and W. by the Adriatic; area, about 13,000 sq. m.; pop. in 1870, 1,041,123. Its breadth is greatest in the W. part, which is traversed by continuations of the Julian Alps, branches of which are the Great and Little Capella ranges, and by the Dinaric Alps, while the easternmost division is crossed by offshoots of the S. E. Carpathians. The middle parts are mostly level and exceedingly fertile. The highest elevations are Mounts Gugu (7,700 ft. high) and Sarka (7,300 ft.), near the Tran-sylvanian boundary, and Mount Klek or Ogulin Head (Ger. Oguliner Kopf) near Zengg on the Adriatic (6,900 ft.). The principal rivers are the Danube, which traverses the country in a S. E. direction between Peterwardein and Sem-lin, continuing its course E. on the southern frontier as far as Orsova, and receiving the waters of the Theiss, the Bega, and the Temes; the Save, which separates the Military Frontier from Bosnia and Servia, and falls into the Danube between Semlin and Belgrade in Servia; and the Kulpa and the Unna, affluents of the Save, flowing respectively on the confines of Croatia and Bosnia. There are some mountain lakes in the W. part.

Of mineral waters, the sulphur springs of Mohadia, near the confines of Wal-lachia, are most celebrated, the place being also famous for picturesque scenery. The climate is very mild in the level country, but severe in the mountains. The principal productions are the various kinds of grain, maize, tobacco, flax, hemp, fruits, and wine; and of minerals, silver, iron, copper, lead, and some gold. The inhabitants are mostly of Slavic race, Croats, Slavonians, Serbs, etc.; but there are also Wallachs, Magyars, Germans, Greeks, Jews, Clementines (Albanians), and gypsies. The predominant religions are the Greek and the Roman Catholic, the former having its centre at Carlovitz on the Danube, the seat of a patriarch or archbishop. There are few towns, but some of them, as Peterwardein, Carlovitz, Semlin, Pan-csova, and Old Orsova, all on the Danube, Zengg, Carlopago, and Brood, in the western division, and others, are important on account of their situation. - The country was originally formed into a military organization by Ferdinand I. (died in 1564) as a barrier against the Turks, and it was reconstituted in 1807 and again in 1850. Under the military organization almost the entire male population above 20 years old was formed into 14 regiments of infantry, 1 of hussars, and 2 battalions of boatmen.

All agricultural estates were the common property I of the Frontier communities, the rural buildings being partly inalienable and partly individual property. Arms, accoutrements, and ammunition, and all necessaries during military service, were supplied by the government, and in all military respects the frontiersmen were subject to the rules of the Austrian army. Before the reorganization of Austria in 1867 the Military Frontier was a separate crown land of the empire. By that reorganization its reunion with the crown of Hungary was virtually established; and at the meeting of the delegations of Cisleithan Austria and Hungary in 1869, it was resolved to abolish gradually the peculiar institutions of the Military Frontier, and to incorporate one of the two military commanderies with Hungary proper, and the other with Croatia. The transformation was nearly completed in 1874.