Final answer:
The Siberian Region is the largest agricultural area in the Russian domain in terms of size, despite being more recognized for its natural resources.
Step-by-step explanation:
The agricultural region that covers the largest area in the Russian domain is the Siberian Region. While the European part of Russia, specifically the Russian Plain, is the most agriculturally productive, the Siberian Region encompasses a vast territory extending to the east of the Ural Mountains. Despite its size, this region is sparsely populated and is known more for its vast natural resources than for agriculture. However, if we consider the expansiveness rather than the productivity of agricultural land, Siberia is the largest.