Learn more about Omri from the Easton’s Bible Dictionary

Servant of Jehovah. When Elah was murdered by Zimri at Tirzah (1 Kings 16:15-27), Omri, his captain, was made king (B.C. 931). For four years there was continued opposition to his reign, Tibni, another claimant to the throne, leading the opposing party; but at the close of that period all his rivals were defeated, and he became king of Israel, "Tibni died and Omri reigned" (B.C. 927). By his vigour and power he gained great eminence and consolidated the kingdom. He fixed his dynasty on the throne so firmly that it continued during four succeeding reigns. Tirza was for six years the seat of his government. He then removed the capital to Samaria (q.v.), where he died, and was succeeded by his son Ahab. "He wrought evil in the eyes of the Lord, and did worse than all that were before him."
Beth-omri, "the house" or "city of Omri," is the name usually found on Assyrian inscriptions for Samaria. In the stele of Mesha (the "Moabite stone"), which was erected in Moab about twenty or thirty years after Omri's death, it is recorded that Omri oppressed Moab till Mesha delivered the land: "Omri, king of Israel, oppressed Moab many days, for Chemosh was angry with his land. His son succeeded him, and he also said, I will oppress Moab" (comp. 2 Kings 1:1; 3:4, 5). The "Moabite stone" also records that "Omri took the land of Medeba, and occupied it in his day and in the days of his son forty years."