The Piadyshev atlas attests to the presence of 576 post houses. In some cases the post house (почтовой двор) was freestanding; in others it was designated as a "post station with a post house". The main distinction between the features in this layer and those in the "Post station" layer are that the latter were located in towns or villages, while the post houses are not located in otherwise populated places.
The main concentrations of post houses occur in the Grand Duchy of Finland and in the Don Cossack territory.
