1 Kings 15:33 contains the formal introduction to Baasha, although his name has previously appeared twice in connection of the continuous warfare between him and King Asa of Judah.
The writer tells us in this verse two things: first, the date of the beginning of his reign—the third year of his Judean counterpart Asa; second, the length of Baasha's rule, twenty-four years. Twenty-four years is a relatively long term of government. Baasha’s predecessor Nadab was king for a maximum of two years, and Baasha’s son Elah was also king for only two years (1 Kings 16:8). This Elah was killed by Zimri, one of his commanders (1 Kings 16:9–10)—but this Zimri reigned for only seven days, until he came to his end in a takeover by his commander Omri (1 Kings 16:18).
Tirzah became the first capital of the northern kingdom of Israel. A later successor to Baasha, Omri, left Tirzah and built a new one capital, Samaria (see 1 Kings 16:23–24). Both places were on what is now called the West Bank.
33 In the third year of Asa king of Judah, Baasha the son of Ahijah began to reign over all Israel at Tirzah, and he reigned twenty-four years.