Internal Migration through History

Internal migration concerns changes of residence within Iran. It must be distinguished from immigration into the country and emigration abroad. It also differs from urbanization: an increase in the population classified as urban does not, by itself, reveal how many people moved. The historical demographic literature identifies changes in the definition of a city and the incorporation of villages into cities as additional reasons urban population totals can increase. s1

Measurement matters just as much as geography. Comparing birthplace with residence identifies a different population from asking whether someone moved during a specified interval. Iran's census history illustrates the problem: the 1996 questionnaire omitted birthplace, interrupting the ability to quantify lifetime migrants using that question. Such a break should not be interpreted as evidence that migration itself diminished. s1

Migration is often imagined as a single journey from a village to a large city. That pathway matters, but it does not describe the whole system. A historical table reproduced in a KNOMAD report shows an increasing urban-to-urban share across successive reporting intervals. The chart below preserves those intervals rather than presenting the observations as annual measurements. s2

The composition of migration and its volume answer different questions. A larger share of moves between urban places does not establish a larger total number of migrants, greater travel distances, or movement exclusively toward Tehran. Nor does this table identify how often an individual moved, whether a move was temporary, or whether a household subsequently returned. s2

The report's account of the 2011–2016 period also identifies contrasting provincial experiences: Semnan, Alborz, and Yazd had high positive migration rates, while Lorestan, Chaharmahal-Bakhtiari, and Ilam had high negative rates. This regional variation is more informative than assuming a uniform national experience. s2

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UNFPA's publication introduction describes several motives, including employment, leaving deprivation, retirement, and seeking a different residential environment. Its examples include movement away from cities as well as toward them. This framing helps explain why a single rural-push or urban-pull story is insufficient, although the introduction alone cannot establish the relative importance of each motive. s3

Environmental conditions also deserve careful treatment. A CESifo working paper using provincial census evidence from 2011 and 2016 reports a positive relationship between aerosol optical depth, a satellite-based pollution measure, and net outmigration. That statistical finding concerns aggregate provincial patterns; it does not identify the reason for every household's move. s4

Read together, these sources support a history of changing destinations and multiple motivations. They also show why contemporary claims require fresh evidence: retrospective census intervals and a later targeted survey cannot supply a continuous national annual migration series. Earlier historical mobility and post-2016 national patterns remain research gaps in this account. s1s2