The Osowiec Fortress, Osowiec-Twierdza
Narodowy Instytut Dziedzictwa pl

A work of defensive architecture and military engineering; an example of Russian military structures of the late 19th century, with great landscape values.


The Osowiec Fortress was built in the years 1882-1892 and 1922-1932 (modernisation and expansion) and in 1939 (expansion), as a barrier fortress representing a part of the larger defence system of the Russian Empire of the late 19th century - the so-called eastern pillar of the Narew-Biebrza line fortifications. The undertaking was preceded by geodesic measurements carried out in the 1870s. The construction and numerous modernisations were interrupted by the Russian-Japanese war, the October Revolution, World War I and II. Main construction engineers included General Eduard Ivanovich Totleiben, Eng., General Rostislav W. Krassowski, Eng., Stabskapitaen Nestor A. Bujnicki. During World War I, the Osowiec Fortress was under siege twice (at the turn of September and October 1914 and between February and August 1915). The fortress garrison repulsed all attacks; the Russians evacuated themselves on 23 August 1915. The Osowiec Fortress was effectively defended against conquest owing to over 190 thousand hectares of the Biebrza River valley, mainly covered with swamps and peatbogs. A system of traps and culverts allowed flooding the area in case of foes’ attack. German troops stationed there until 1919. When Poland regained independence, a military unit of the reactivated Polish Military took over the fortress. After the September Campaign, the building went into the Red Army’s hands. After a short German governance, the Polish military unit has stationed in the Osowiec Fortress since 1953.


The fortress is located in place of a former Biebrza crossing, close to the Odessa-Konigsberg railway line built in 1873. Fortifications begin 3.5 km west of Goniądz and stretch along the left bank of the Biebrza River for 6.5 km. The fortress plan is similar to a right triangle, where the defence front along the Biebrza River ran along a line of 6.5 km. The fortress wings sheltered by field fortifications guaranteed the length of defended front of up to 16-18 km. Component parts: Fort I, Skobelev Mountain, interfields of Fort I and III, Fort II with a river bank position, Fort III-Swedish, Fort IV (the first reinforced concrete fort erected in Russia) and interfield of Fort IV. The fortress consists of ramparts and earthen structures, into which fort buildings were incorporated (gates, combat shelters, barracks, powder houses, warehouses, caponiers, posterns, roads, squares, yards, a military cemetery and a system of moats and canals, traps, culverts and bridges). The style, characteristic for military architecture found in the former Russian partition at the turn of the 19th and 20th century, is distinctive for its monumental façades of yellow or red brick, partitioned by means of elements of classical orders (pilasters, entablature); pilasters rest on rusticated plinths and support entablature consisting of a smooth architrave, cubical frieze and profiled cornice. They are all supported by a string course. This type of structures later became a model for numerous residential buildings, widely spread across the former Russian partition. The basic construction material is earthen structures of embankments, with triangular or trapezoid sections, with a width of base ranging from several to several dozen metres and the height between 2 and 22 metres, as well as wet and dry fortress ditches. Particular fortress features are made of brick, brick and concrete, concrete or reinforced concrete.

Part of the feature is available to visitors with a tourist guide; a part occupied by the military is inaccessible.

compiled by Iwona Górska, Regional Branch of the National Heritage Board of Poland in Bialystok, 05-07-2014.


  • Karta ewidencyjna, Twierdza Osowiec, oprac. Wap A., 1996, Archiwum Wojewódzkiego Urzędu Ochrony Zabytków w Białymstoku oraz Archiwum Narodowego Instytutu Dziedzictwa.
  • Wap A., Twierdza Osowiec. Zarys dziejów, Białystok 1994.
  • Górska I., Architektura militarna, [w:] Górska I., Kotyńska-Stetkiewicz J., Kułak A., Ryżewski G., Perły Architektury województwa podlaskiego, Białystok 2010, s. 118-122.

General information

  • Type: defensive architecture
  • Chronology: 1882-1892
  • Form of protection: register of monuments
  • Address: Osowiec-Twierdza
  • Location: Voivodeship podlaskie, district moniecki, commune Goniądz - obszar wiejski
  • Source: National Heritage Board of Poland


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