Albert Barnes Commentary 1 Kings 16:8

"In the twenty and sixth year of Asa king of Judah began Elah the son of Baasha to reign over Israel in Tirzah, [and reigned] two years." — 1 Kings 16:8 (ASV)

Two years—that is, more than one year, or, at any rate, some portion of two distinct years (compare 1 Kings 16:10).