Tehrân, the capital and largest city, serves as the main administrative, commercial, educational, financial, industrial, and publishing center.Throughout Iran there are mosques. Iran's other major cities include Mashhad, a manufacturing and commercial center. In the northeast and the site of the country's most important religious shrine; Efahân, a manufacturing center for central Iran with several architecturally significant public buildings from the 17th and 18th centuries; Tabrîz, the main industrial and commercial center of the northwest; Shîrâz, a manufacturing center in the south, the commercial and manufacturing center in the southwestern oil region.

The population of Iran was estimated at 68,959,93168,959,931) in 1998. This number has more than double the 1975 population of 33,379,000. Between 1956 and 1986 Iran's population grew at a rate of more than 3 percent per year. The growth rate began to decline in the mid-1980s after the government initiated a major population control program. By 1998 the growth rate had declined to 2.042.04) percent per year, with a birth rate of 31 per 1,000 persons and a death rate of 6 per 1,000. In 1998, 44 percent of the population was under age 15, 53 percent was between 15 and 64, and only 4 percent was aged 65 or older.

Overall population density in 1998 was 42 persons per sq km (108 per sq mi). Northern and western Iran are more densely populated than the dry eastern half of the country, where population density in the broad desert regions is only 1 percent of the national average. In 1997, 60 percent of the population lived in urban areas. About 99 percent of rural Iranians resided in villages. Only 240,000 were nomads, a fraction of the 2 million nomads counted in 1966.