Brunswick (Ger. Braunschweig), a sovereign duchy of northern Germany, and a constituent state of the German empire, comprising three larger and six smaller portions of territory. The principal or northern part, containing the towns of Brunswick, Wolfenbüttel and Helmstedt, is situated between the Prussian provinces of Hanover and Saxony to the south-east of the former. The western part, containing Holzminden and Gandersheim, extends eastward from the river Weser to Goslar. The Blankenburg, or eastern portion, lies to the south-east of the two former, between Prussia, the duchy of Anhalt and the Prussian province of Hanover. The six small enclaves, lying in the Prussian provinces of Hanover and Saxony, are the districts Thedinghausen, Harzburg and Kalvörde, and the three demesnes of Bodenburg, Olsburg and Ostharingen. A portion of the Harz mountains was, down to 1874, common to Brunswick and Prussia (Hanover) and known as the Communion Harz. In 1874 a partition was effected, but the mines are still worked in common, four-sevenths of the revenues derived from them falling to Prussia and the remaining three-sevenths to Brunswick.

The northern portion of the duchy has its surface diversified by hill and plain; it is mostly arable and has little forest. The other two principal portions are intersected by the Harz mountains, and its spurs and the higher parts are covered with forests of fir, oak and beech. The greatest elevations are the Wurmberg (3230 ft.), and the Achtermannshöhe (3100 ft.), lying south of the Brocken. Brunswick belongs almost entirely to the basin of the river Weser, into which the Oker, the Aller and the Leine, having their sources in the Harz, discharge their waters. The climate is mild in the north, but in the hilly country raw and cold in winter, and in autumn and spring damp. The area of the duchy is 1424 sq. m., and of this total fully one-half is arable land, 10% meadow and pasture, and 33% under forest. The population in 1905 was 485,655. The religion is, in the main, that of the Lutheran Evangelical church; but there is a large Roman Catholic community centred in and round Hildesheim, the seat of the bishopric of North Germany. The Jews have several synagogues, with a rabbinate in Brunswick. The birth-rate is 35.3, and the death-rate 21.6 per thousand inhabitants.

In the rural districts, broad Low German is spoken; but the language of the upper and educated classes is distinguished by its purity of style and pronunciation.

The land devoted to agriculture is excellently farmed, and cereals, beet (for sugar), potatoes and garden produce of all kinds, particularly fruit, obtain the best market prices. The pasture land rears cattle and sheep of first-rate quality, and great attention is paid to the breeding of horses, in which the famous stud farm at Harzburg has of late years been eminently conspicuous. Timber cutting, in the forests of the Harz, employs a large number of hands. But agriculture, which, until recently, formed the chief wealth of the duchy, has now given way to the mining industry, both in point of the numbers of inhabitants employed and in the general prosperity distributed by it. The chief seat of the mining industry is the Harz, and its development annually increases in extent and importance. Coal (bituminous), iron, lead, copper, sulphur, alum, marble, alabaster, lime and salt are produced in large quantities, and the by-products of some of these, particularly chemicals and asphalt, constitute a great source of revenue. The manufactures embrace sugar (from beet), spinning, tobacco, paper, soap machines, glass, china, beer and sausages. The last are famous throughout Germany. The principal articles of export are thread, dyes, cement, chicory, beer, timber, preserves, chemicals and sausages.

The railways, formerly belonging to the state, were, in 1870, leased to private companies and in 1884 purchased by Prussia, and have a length of about 320 m. The roads, of which one quarter are in the hands of the state, are excellently kept, and vie with those of any European country.

The constitution is that of a limited monarchy, and dates from a revision of the fundamental law on the 12th of October 1832. The throne is hereditary in the house of Brunswick-Lüneburg, according to the law of primogeniture, and in the male line of succession, but the rightful heir, Ernest, duke of Cumberland, was not allowed to take possession. The parliament of the duchy (Landes- or Ständeversammlung) is an assembly of estates forming one house of 48 deputies, of whom 30 are elected by municipal and rural communities, while the remainder represent the Evangelical church, the large landed proprietors, manufacturers and the professions. The house, however, has little power in initiating legislation, but it can refuse taxation, impeach ministers and receive petitions. The executive functions of the administration and government reside in the ministry (Staatsministerium) consisting of three responsible ministers, assisted by a council of the holders of the other chief offices of state. The public debt amounts to about 3¼ millions sterling, and the civil list to about £56,000 a year, mostly derived from the revenues of the state domains.

By virtue of a convention with Prussia, of March 1886, the Brunswick contingent to the imperial forces forms a part of the Prussian army and is attached to the X. army corps. The convention can be rescinded only after a two years' notice.