The Elburz Range forest steppe ecoregion is an arid, mountainous 1,000-kilometer arc south of the Caspian Sea, stretching across northern Iran from the Azerbaijan border to near the Turkmenistan border. It covers 63,300 square kilometres (24,400 sq mi) and encompasses the southern and eastern slopes of the Alborz Mountains as well as their summits. The Caspian Hyrcanian mixed forests ecoregion, with its lush green mountainsides and plains that receive moisture from the Caspian Sea, forms this ecoregion's northern border. The vast Central Persian desert basin ecoregion forms its southern border.