Oman proper (Arabic: عُمان الوسطى‎ ʿUmān al-Wusṭā) refers to a historical area within the present-day Sultanate of Oman. It lay inland from Muscat beyond the Jebel Akhdar (Green Mountains) and was centered on the city of Nizwa in the area of the current region of Ad Dakhiliyah.