Polochans were a tribe

Tribe

A tribe, viewed historically or developmentally, consists of a social group existing before the development of, or outside of, states.Many anthropologists use the term tribal society to refer to societies organized largely on the basis of kinship, especially corporate descent groups .Some theorists...

 of early East Slavs

East Slavs

The East Slavs are Slavic peoples speaking East Slavic languages. Formerly the main population of the medieval state of Kievan Rus, by the seventeenth century they evolved into the Russian, Ukrainian, and Belarusian peoples.-Sources:...

, who inhabited the area in the middle of the Western Dvina in the 9th century. Alternative meaning: inhabitants of Polotsk.

They are mentioned in the Primary Chronicle

Primary Chronicle

The Primary Chronicle , Ruthenian Primary Chronicle or Russian Primary Chronicle, is a history of Kievan Rus' from about 850 to 1110, originally compiled in Kiev about 1113.- Three editions :...

, which explains that the name "polochans" derived from the Polota River, Western Dvina's tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

. It further says that Krivich

Krivich

The Krivichi was one of the tribal unions of Early East Slavs between the 6th and the 12th centuries. They migrated to the mostly Finnic areas in the upper reaches of the Volga, Dnieper, Western Dvina, areas south of the lower reaches of river Velikaya and parts of the Neman basin.-Etymology:Many...

s were descendants of Polochans. The lands of the Polochans spanned towards the upper reaches of the Śvisłač River on the south and along the left bank of the Biarezina River to the lands of the Dregovichs

Dregovichs

The Dregoviches were one of the tribal unions of Early East Slavs, and inhabited the territories down the stream of the Pripyat River and northern parts of the right bank of the Dnieper river...

. The Polochan lands bordered with the following tribes:

• To the southeast - Smolensk
  Smolensk
  Smolensk is a city and the administrative center of Smolensk Oblast, Russia, located on the Dnieper River. Situated west-southwest of Moscow, this walled city was destroyed several times throughout its long history since it was on the invasion routes of both Napoleon and Hitler. Today, Smolensk...
  
   Krivichs;
• To the north and east - Izborsk
  Izborsk
  Izborsk is a rural locality in Pechorsky District of Pskov Oblast, Russia. It contains one of the most ancient and impressive fortresses of Western Russia....
  
   Krivichs and Novgorod Slavs;
• To the west - Lithuanian
  Lithuanians
  Lithuanians are the Baltic ethnic group native to Lithuania, where they number around 2,765,600 people. Another million or more make up the Lithuanian diaspora, largely found in countries such as the United States, Brazil, Canada, Colombia, Russia, United Kingdom and Ireland. Their native language...
  
   tribes.

The Polochan tribe was one of the tribes which would later form the Principality of Polotsk.