East Slavs

Russians ( ) are an East Slavic ethnic group native to Eastern Europe. Their mother tongue is Russian, the most spoken Slavic language. The majority of Russians adhere to Orthodox Christianity, ever since the Middle Ages. By total numbers, they compose the largest Slavic and European nation.

Ukrainians (, ) are an East Slavic ethnic group native to Ukraine. Their native tongue is Ukrainian, and the majority adhere to Eastern Orthodoxy. At around 46 million worldwide, Ukrainians are the second largest Slavic ethnic group after Russians.

thumb|An American Cossack family in the 1950s thumb|A Siberian Cossack [[family in Novosibirsk, after 2000]] thumb|Cossacks marching in Red Square at the 2015 Victory Day Parade

Belarusians ( ) are an East Slavic ethnic group native to Belarus. They natively speak Belarusian, an East Slavic language. More than 9 million people proclaim Belarusian ethnicity worldwide. Nearly 7.99 million Belarusians reside in Belarus, with the United States and Russia being home to more than 500,000 Belarusians each. The majority of Belarusians adhere to Eastern Orthodoxy.

Rusyns, also known as Carpatho-Rusyns, Carpatho-Russians, Ruthenians, or Rusnaks, are an East Slavic ethnic group from the Eastern Carpathians in Central and Eastern Europe. They speak Rusyn, an East Slavic language variety, treated variously as either a distinct language or a dialect of the Ukrainian language. As traditional adherents of Eastern Christianity, the majority of Rusyns are Eastern Catholics, though a minority of Rusyns practice Eastern Orthodoxy.

Slavic peoples speaking the East Slavic languages (Belarusian, Russian, Rusyn, Ukrainian people); formerly the main population of the Kievan Rus

The Poleshuks, or Polishchuks, also known as Polesians (, , , ) are the indigenous population of Polesia (also known as Polesie and Polissia). Their native speech forms a dialect continuum between the Belarusian and Ukrainian languages and includes recently codified West Polesian, as well as many local variations and sub-dialects.

Podlashuks (Podlachian: Пудляшуки, Pudliashuki; ; ; ) are an East Slavic ethnic group from Podlachia, a historical region in northeastern Poland which includes the Podlaskie and Lublin Voivodeships. Some Podlashuks identify as Belarusian, Ukrainian, or Polish, while others identify as a distinct ethnic group.