 The narrow valley of the Vipava River serves as the main passage between the Friulian lowland and central Slovenia, and is thus also an important corridor connecting Northern Italy to Central Europe.It is closed to the north by the high Trnovo Forest Plateau (), and to the south by the Karst Plateau and the narrow Branica Valley, a geographical sub-unit of the Vipava Valley.It is named after the Vipava River.