Diyala Governorate is a governorate in eastern Iraq on the border with Iran. Diyala's capital is the city of Baqubah, and it is named for the Diyala River, a tributary of the Tigris. The province's agriculture includes the largest olive groves in the Middle East as well as the most oranges in the whole region. Diyala was once dominated by a Sunni Muslim Arab majority, but following the 2003 overthrow of Saddam Hussein and retribution by Shi'ites and Kurds, the Sunni majority dropped as 50% of the governorate became Shia as Shi'ites occupied the vacant homes and farms of fleeing Sunnis.