This information was donated by JP.
Usvyat/Usvyaty: surname variations derived from the town's name include: USVYAT, USVYATOV, USVYATSEV, USVYATSKY and possibly SVIATSKIN and SVYATSKY.
Usvyat and Usvyaty are 2 very tiny shtetlach about 4 km from each other, are situated on the Russian-Belorussian border, on the Usvyatka River and near the Usvyatskoe Lake. The town is located between Smolensk and Nevel, (the railway station on the St. Petersburg to Vitebsk railroad). This is in a heavily forested region; therefore many people were involved in the lumber trade, or in related trades such as carpentry. There weren’t many other economic opportunities in the region.
Usvyaty had a substantial Jewish population in the 19th and early 20th centuries, many of whom were Chabad Chassidim.
It was fairly common for people from present day Belarus to make their way to places like Odessa. The general trend in internal migration in the Russian Empire was from north to south, and in the 19th century the government encouraged people to move from places like Usvyaty to the "New Russia" in and around Odessa.
The following record set information was translated and abstracted by DB.
There are websites which give information about Ustvaty.