Терек
The earliest known records of Slavic settlements on the lower Terek River date to 1520 when the Ryazan Principality was annexed by the Grand Duchy of Moscow and a lone group left and settled in the natural haven of the Terek River (modern northern Chechnya). The early settlement was located at the mouth of the Aktash River. This formed the oldest Cossack group, the Greben Cossacks (Гребенские казаки "Grebenskiye Kazaki") who settled on both banks of the river.