Harju County, is one of the fifteen counties of Estonia. It is situated in northern Estonia, on the southern coast of the Gulf of Finland, and borders Lääne-Viru County to the east, Järva County to the southeast, Rapla County to the south, and Lääne County to the southwest. The capital and largest city of Estonia, Tallinn, is situated in Harju County. Harju is th…Harju County, is one of the fifteen counties of Estonia. It is situated in northern Estonia, on the southern coast of the Gulf of Finland, and borders Lääne-Viru County to the east, Järva County to the southeast, Rapla County to the south, and Lääne County to the southwest. The capital and largest city of Estonia, Tallinn, is situated in Harju County. Harju is the largest county in Estonia in terms of population, as almost half of Estonia's population lives in Harju County.