A Cossack host or Cossack viysko (Козаче військо, kozache viysko, sometimes incorrectly translated as Cossack Army) was an administrative subdivision of Cossack

Cossack

Cossacks are a group of predominantly East Slavic people who originally were members of democratic, semi-military communities in what is today Ukraine and Southern Russia inhabiting sparsely populated areas and islands in the lower Dnieper and Don basins and who played an important role in the...

s in Imperial Russia. The word host is an archaic word for army, and also can mean "a great number; multitude".

Imperial Russia

The Cossack host consisted of a certain territory with Cossack settlements that had to provide military regiments for service in the Imperial Russian Army

Imperial Russian Army

The Imperial Russian Army was the land armed force of the Russian Empire, active from around 1721 to the Russian Revolution of 1917. In the early 1850s, the Russian army consisted of around 938,731 regular soldiers and 245,850 irregulars . Until the time of military reform of Dmitry Milyutin in...

 and for border patrol. Usually the hosts were named after the regions of their dislocation. The stanitsa

Stanitsa

Stanitsa is a village inside a Cossack host . Stanitsas were the primary unit of Cossack hosts.Historically, the stanitsa was a unit of economic and political organisation of the Cossack peoples primarily in the southern regions of the Russian Empire.Much of the land was held in common by the...

, or village, formed the primary unit of this organization.

Cossack voiskos on Russian soil were disbanded in 1920, at the end of the Russian Civil War

Russian Civil War

The Russian Civil War was a multi-party war that occurred within the former Russian Empire after the Russian provisional government collapsed to the Soviets, under the domination of the Bolshevik party. Soviet forces first assumed power in Petrograd The Russian Civil War (1917–1923) was a...

. Those Cossacks who settled abroad continued to preserve the traditions of their hosts (i.e. the Triunited Don-Kuban-Terek Cossack Union).

In the Russian Empire

Russian Empire

The Russian Empire was a state that existed from 1721 until the Russian Revolution of 1917. It was the successor to the Tsardom of Russia and the predecessor of the Soviet Union...

, the Cossacks constituted eleven separate hosts, settled along the frontiers: the Don, Kuban, Terek

Terek Cossack Host

The Terek Cossack Host was a Cossack host created in 1577 from free Cossacks who resettled from the Volga to the Terek River. In 1792 it was included in the Caucasus Line Cossack Host and separated from it again in 1860, with the capital of Vladikavkaz...

, Astrakhan, Ural

Ural Cossack Host

The Ural Cossack Host was a cossack host formed from the Ural Cossacks -- those cossacks settled by the Ural River. Their alternative name, Yaik Cossacks, comes from the old name of the river.- History :...

, Orenburg, Siberian

Siberian Cossacks

Siberian Cossacks were Cossacks who settled in the Siberian region of Russia from the end of the 16th century, following the Yermak Timofeyevich's conquest of Siberia. In early Siberia practically the whole Russian population, especially the serving-men were called Cossacks, but only in the loose...

, Semiryeche, Transbaikal, Amur, and Ussuri.

There was also a small number of the Cossacks in Krasnoyarsk

Krasnoyarsk

Krasnoyarsk is a city and the administrative center of Krasnoyarsk Krai, Russia, located on the Yenisei River. It is the third largest city in Siberia, with the population of 973,891. Krasnoyarsk is an important junction of the Trans-Siberian Railway and one of Russia's largest producers of...

 and Irkutsk

Irkutsk

Irkutsk is a city and the administrative center of Irkutsk Oblast, Russia, one of the largest cities in Siberia. Population: .-History:In 1652, Ivan Pokhabov built a zimovye near the site of Irkutsk for gold trading and for the collection of fur taxes from the Buryats. In 1661, Yakov Pokhabov...

, who would form the Yenisey Cossack Host and Irkutsk

Irkutsk

Irkutsk is a city and the administrative center of Irkutsk Oblast, Russia, one of the largest cities in Siberia. Population: .-History:In 1652, Ivan Pokhabov built a zimovye near the site of Irkutsk for gold trading and for the collection of fur taxes from the Buryats. In 1661, Yakov Pokhabov...

 Cossack Regiment

Regiment

A regiment is a major tactical military unit, composed of variable numbers of batteries, squadrons or battalions, commanded by a colonel or lieutenant colonel...

 of the Ministry of the Interior in 1917.

Other hosts

Other Cossack hosts included the:

• Zaporozhian Host — the Zaporozhian Cossacks who lived in Zaporizhia
  Zaporizhia
  Zaporizhia or Zaporozhye [formerly Alexandrovsk ] is a city in southeastern Ukraine, situated on the banks of the Dnieper River. It is the administrative center of the Zaporizhia Oblast...
  
  , in Central Ukraine
  Ukraine
  Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...
  
   during the 16th — 18th centuries.
• Danube Cossack Host
  Danube Cossack Host
  The Danube Cossack Host was an Imperial Russian Cossack Host formed in 1828 prior to the Russo-Turkish War , on the order of Emperor Nicholas I from descendants of the Zaporozhian Cossacks living in Bessarabia and in particularly the Budjak. Russian Cossack Host named Lower-Danube Budjak Host had...
  
   — an Imperial Russian Cossack Host formed from descendants of the Zaporozhian Cossacks.