If you google “Ten Lost Tribes of Israel,” you’ll get more than 400,000 hits. It’s a popular topic, and there are fanciful imaginings aplenty about where they might be.
The problem is that the tribes were never lost. Recall that the Kingdom was divided in the days of Rehoboam and Jeroboam, and that ten of the twelve tribes sided with the Northern Kingdom of Israel. And this Northern Kingdom was subsequently sacked and taken into exile by the Assyrians in the 700s BC. And the Assyrians repopulated the area with other ethnic groups, and they intermarried with the Israelites who were left behind, leading to the mongrelized Samaritans.
But the crucial fact that’s often missed is that there were members of the Ten Tribes living in the Southern Kingdom of Judah. We know them as the faithful remnant of Israel. Check it out:
2 Chronicles 11:13-16 (ESV, emphasis and clarification mine)
13 And the priests and the Levites who were in all Israel presented themselves to [Rehoboam] from all places where they lived. 14 For the Levites left their common lands and their holdings and came to Judah and Jerusalem, because Jeroboam and his sons cast them out from serving as priests of the LORD, 15 and he appointed his own priests for the high places and for the goat idols and for the calves that he had made. 16 And those who had set their hearts to seek the LORD God of Israel came after them from all the tribes of Israel to Jerusalem to sacrifice to the LORD, the God of their fathers.
And this wasn’t the only time faithful Israelites fled from the Northern Kingdom. It happened again when Rehoboam’s grandson (Asa, a good king) was reigning.
2 Chronicles 15: 9 (ESV, emphasis and clarification mine)
9 And [Asa] gathered all Judah and Benjamin, and those from Ephraim, Manasseh, and Simeon who were residing with them, for great numbers had deserted to him from Israel when they saw that the LORD his God was with him.
Just some food for thought.