The article examines the situation of Tara uyezd and service people who lived in the town of Tara in the first third of the 18th century. The research relies on such archival materials as responses of officials of Tara uyezd who completed to Prof. G.F. Miller’s questionnaire, books and tables of Siberian prikaz on the servitors in Siberia, and materials from the Senate fund. The article provides data on the town of Tara and Tara uyezd in the 1730s. Tara had a near-border position. A large Oirat state -Dzungar Khanate - was located to the south of Tara, and noble Oirat nomads collected tribute from the Turkic population of the uyezd. The reforms of Peter I made profound changes in the social world of Siberia. In the first third of the 18th century, the composition of the uyezd’s population was significantly altered. A new social group raznochintsy was formed of the relatives of servitors and clergy, and a large part of Tara’s service people were transferred to the garrison regiments of Siberia and the Orenburg governorate. The conflict between Tara’s horse Cossacks and captain Yakov Cheredov is indicative and important for understanding the service in favor of the state at that time. The Cheredovs were a deep-rooted clan of Russian service people who had lived in Tara since its founding. The Cheredovs held a number of important offices in Tara, and many of them became Boyar scions and nobles. After the 1722 Tara Rebellion, in which the Cheredovs played a significant role, they lost their privileged position and became raznochintsy . The ‘old’ service people who were nobles, Boyar scions and Cossacks remained the main military force in Siberian uyezds after the reforms. However, their dependence on the state increased. New garrison regiments in the region were formed in the 1730s, mostly of ‘old’ service people.