Upvote:28
Maybe I shall make it a comment, but it is not totally clear whether you mean (1) or (2):
(1) did 12 tribes exist or,
(2) yes we know 12 tribes existed, but where did 10 of those tribes disappear to?
Regarding issue (1), the answer is positive. Archeological excavations uncovered, within the territory of Israel, all 12 tribe-cities of all 12 tribes. I personally was on the excavated site of Dan, on the Dan river in the north of Israel. So regarding the pre-existance of 12 tribes, archeology says yes. This is a really fascinating archeological finding. It was facilitated by the fact that Bibles give exact or approximate places where the tribe-cities were located, and in many cases, topological names remained the same as given in the Bible. You can look up books about "Bible and archaeology", there are amazing books on this topic, or you can travel to Israel to visit those places.
Much more debate (and fantasies) were generated by issue (2) -- where they disappeared to.
Apparently they suffered intermixing and loss of identity. With the stengthening of central power in ancient Israel, boundaries between the tribes were becoming weaker and people intermixed. It is not really clear whether they intermixed with the rest of Israel, or outside (assimilation) during deporatation, or were they killed or enslaved during deportations.