Кто был первым исследователем Сибири среди русских?
Demid Sofonovich Pyanda () or, according to some sources, Panteley Demidovich Pyanda (), also spelled Penda () (? – after 1637) was among the first and most important Russian explorers of Siberia. According to few historical documents and later reconstructions based on them, Pyanda, in 1620-1623, while leading a party which was hunting for Siberian furs and buying them from the locals, became the first known Russian to ascend the Lower Tunguska River and reach the proximity of the Lena, one of the world's greatest rivers. According to later legendary accounts, collected a century after his journey, Pyanda allegedly discovered the Lena River, explored much of its length, and via the Angara River returned to the Yenisey, whence he came. 
Demid Sofonovich Pyanda