ostan (province), northern Iran, bounded by the ostans of Khorasan on the east, Esfahan on the south, Markazi (Tehran) on the west, and Mazandaran on the north. The northern half of the region is an extension of the Elburz Mountains pierced by narrow defiles; to the south the land surface drops gradually by shallow terraces to the flat salt waste of the Kavir-e Namak. The Rudkhaneh-ye (stream) Qareh Su, rising in the Elburz Mountains, flows southward into the Kavir-e Namak. Most of the population is engaged in agriculture; corn (maize), tobacco, cotton, sugar beets, indigo plants, and fruit are the chief products. Industries produce sugar, ginned cotton, milled flour, bricks, alcoholic beverages, carpets, and leather goods. Chromium, lead, and coal are mined. Roads and rail service link Semnan (the capital) with Lasjerd, Amirabad, Damghan, Emamshahr (formerly Shahrud), and Mayamey. Area 37,641 square miles (97,491 square km). Pop. (2006) 589,742.
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