Poleszuk (Polish), Poliszuk or Polishchuk (local Ukrainian dialect), Palyashchuk (Belarusian), or Poleshchuk (Russian) is the name given to the people who populated the swamps of Polesie.
When asked for their nationality, they usually answered tutejszy ("I am local"), so during a census in the Polish part of the Russian Empire they were generally categorized as "others" or, depending on their religion, as "Poles" or "Belarusians". (A similar thing was reported to happen in other places, for example in the province of Wilno.)
The Primary Chronicle uses the name Dregovichs for an ancient Slavic tribe settled between Pripyat and Western Dvina rivers. The name comes from the Slavic word dregva or dryhva ("swamp"). This tribe is thought to be the ancestors of modern Poliszuks.
The Poleszuk dialect, close to the Ukrainian, Belarussian and Polish languages, was recently assigned as a dialect of Ukrainian.
Nowadays the Poleszuk national identity remains strongest in Belarus. There were around 800,000 of them in 1931. The population of the Polish and Ukrainian parts of Polesie have assimilated with the respective nations.
At the end of 1980s, there was a minor campaign in Belarus for creation of a separate "Polisian language" based on the Polesie dialects. However, they have received no support, so the campaign came to nought eventually.