The author carried out the modeling of the historical dynamics in Russian rural population size from the 18th to the mid-19th century, examined through the case of a single estate in Kostroma province. This relatively small estate was separated from the extensive holdings of the widow of boyar F.I. Mstislavskii in the second quarter of the 17th century and existed within virtually unchanged boundaries up to the abolition of serfdom in 1861. The estate passed through the hands of several owners, including members of the highest Russian aristocracy (the L’vovs, Romodanovskiis, and Lopukhins) in the 17th and first half of the 18th centuries. A corpus of archival documents has been preserved in the Russian State Archive of Ancient Acts and the State Archive of Kostroma Region, including land survey materials and census books from eight revisions, which enables reconstruction of the estate’s history over the entire period. The estate never experienced large-scale devastation, epidemics, or resettlements and can therefore be regarded as a closed system. It thus provides a valuable testing ground for quantitative, formalized approaches at the micro-level. The article develops an approach based on the mathematical apparatus of the theory of branching processes, a branch of mathematical statistics, which constitutes the main innovation of the study. The proposed methodology makes it possible to estimate the value of the natural increase coeffi cient in the next generation even in cases where the revision data are partially incomplete, to approximate the size of each generation not recorded in the censuses, which is of considerable relevance. This applies not only to the male but also to the female population. This is especially important for the 17th century and the first half of the 18th, when women were not enumerated. Besides, the author obtains an approximate estimate of underregistration of the estate’s population during the first revision of 1719–1722, which proves to be substantial, though not as large as mentioned in some leading Russian works.