the Tribe of Judah: Reigned Over Alone by David Seven Years and a Half
Source: TTT
2 Samuel 2:11
And the length of time that David was king in Hebron over the house of Judah was seven years and six months.
2 Samuel 5:5
In Hebron he reigned over Judah seven years and six months, and in Jerusalem he reigned thirty-three years over all Israel and Judah.