Klešniku Bog (Zabolotjes Bog) is located in the eastern part of the former Ludza district, by the border between Russia and Latvia, on the Zilupes valley.

Its area is 2,197 ha; the largest part (1,720 ha) is the raised bog; 412 ha – transition bog; in the northern part there is a low bog (65 ha).

Average depth of the peat layer is 3.7 m; the deepest one reaches 7.8 m.

Total deposit of peat: 76.6 mil.m3

Peat in the raised bog up to 3 m deep has not decayed; the deeper peat is medium and well decayed; under the peat there is sapropel. Peat in the transition and low bog is medium and well decayed. The bog appeared in Pīteļa delve, when land became muskeg. The largest part of the bog is open, in some places there are sparse pine trees. 1,736 ha of the bog is the Klešniku natural reserve.  

Latvijas daba. 6.sēj. – Rīga: Latvijas enciklopēdija, 1998. – P. 103.