Provinces were the building blocks of the imperial administrative structure. Starting in the 18th century, provinces came in two forms: the guberniia and the oblast'. Empress Catherine II determined the shape and structure of the former, dominant form, with her 1775 Statute on Guberniia Administration (law number 14392). At that time there were 40 gubernii; by the 1820s there were 49, the geography of which corresponds - some argue - to the geography of the core of the Russian Empire.
Included here are the 7 gubernii of the Grand Duchy of Finland as well, bringing the total number of gubernii shown on the atlas to 56.
The guberniia was a secondary administrative unit.
