Not quite. You are thinking of the Book of Mormon, which describes how two small groups migrated from Judea to the Americas about the time of the Babylonian Captivity (ca 600 BC). These groups mixed with other people in the Americas; some of their descendants are among the American Indians today.
The Ten Tribes were carried away captive by the Assyrians earlier (722 BC). The present location of the Ten tribes is unknown to us; however, Mormonism teaches that God will restore them in time.
Isn't the book of Mormon used by Mormons for the basis of their belief system?
I forgot to mention that the Book of Mormon also speaks of another small group that migrated to the Americas about the time of the Tower of Babel. They were not Israelites. Some of their descendants likely exist among the American Indians today.
Some folks would disagree with your statement here....about not knowing where they are today, but I can tell you from scripture that these ten tribes were known as "Israel", the northern kingdom. The Biblical history of Israel ends in [2Kings 17] except for the prophets. The people occupying the middle east nation called "Israel" today are descendants of the southern kingdom of Judah, [2 Kings 17:18] and became known as Jews.
All throughout the rest of the Old Testament....and the New, you will see prophecy directed to or against both "Israel and Judah". To understand this prophecy make sure you only apply prophecy about "Judah" to the present day, misnamed country of Israel. The rest of the prophecy regarding "Israel" is directed to or against some other group of folks.....to be named later.
There is a very broad distinction in the Bible between these two nations. In fact the very first place you will find the word Jew mentioned in scripture is 2 Kings 16:5-6 and Israel is at war against the Jews. This is one reason why so many folks cannot understand simple prophecy. They are trying to place the wrong events on the wrong people at the wrong time.