At the head of the Gulf the linguistic boundary between Arabic and the Iranian dialects does not in fact correspond with the fairly well established political boundary. The latter goes up the Shatt al-Arab to just above Khorramshahr on the Persian side opposite Abu Khasib on the Iraqi side and then generally northwards across the plain, keeping about 15-30 kilometres to the east of the Tigris until it reaches the foothills of the Zagros range, where it follows the line of the mountains in a northwesterly direction, as shown in Fig. 8.1. The linguistic boundary, in contrast, crosses this on a northwesterly axis, with Arabic being spoken on the plain and Iranian dialects (in which I include Kurdish) on the high ground. Thus we have Arabicspeaking populations in Iran and Kurdish-speaking populations in Iraq. In the southern Persian region of Khuzistan the native population is uniformly Arabic, although the growth of the oil industry resulted in substantial immigration from the Persian-speaking areas to the oil towns of Abadan and Ahwaz. Ironically also the Iraqi invasion of Khuzistan, which had mistakenly expected Khuzistani Arab support, resulted in considerable displacement of the Arab population to the more northern cities.