ENThe article discusses the documents that mentioned the 19th century Klevai County, and provides information about the owners of Veisiejai and Klevai manor. The oldest document discovered by the author of the article is the letter of the Veisiejai landowner to the Governor of Seinai County regarding the appointment of the Klevai landowner Antanas Borevičius (Antoni Borewicz) as the mayor of the Veisiejai and Klevai counties. The following qualification documents are attached to the letter: the certificate of the Bank of Poland of the Kingdom of Poland regarding the property and employed employees, birth certificate, the certificate of entry in the Klevai County Population Register, school certificate, the certificate of belonging to a secret society, the certificate of oath to the country manager (homagium). The Klevai County is mentioned in the description of Jurgis Šumskis (Jerzy Szumski) Wstęp do inwentarza zespołu ,,Komisarz do spraw włościańskich powiatu sejneńskiego z lat 1864-1913, which is preserved in the Suvalkai State Archives. The second page of the description reads: Klevai County was annexed to the Krasnavas County in the eight decade of the 19th century. The document of 1847 is very interesting, which is related to the letter, in which the governor of Seinai County presents the register of residential houses of Klevai County compiled on September 18, 1847. The houses were divided into 2 groups (classes). The first group consisted of the houses of the manor, folwark, tavern, blacksmith, miller, bricklayer and other manor craftsmen, peasants performing bondage with their horses or oxen and work tools, small landowners, quitrenters with at least 15 morgens of land. The second group included the manor houses, which were inhabited by mercenaries, servants, and hired poor workers, peasants without their own tools and horses, and poor quitrenters.