Where did Abraham and his relatives settle from where had they come and why did they leave?

Abraham (18th century BCE) was born in Ur (Mesopotamia; now Iraq), where he first repudiated idolatry. He then sojourned in Harran (Syria) for several years, and then, at God's command, lived most of his life in Canaan (Israel).
It was in Canaan that Abraham lived most of his life, made a covenant with God (Genesis ch.15), and raised a family to be the center of carrying on his traditions (Genesis 18:19).

Abraham's family carried on his teachings voluntarily. Judaism as a binding, permanent entity, was set forth between God and the Israelite nation descended from Abraham, Isaac and Jacob at Mount Sinai in the time of Moses (Exodus ch.19, ch.24, and 34:27).All of the above places are in the ancient Fertile Crescent.

See also:Where did the Jews come from?
How Judaism was founded

Archaeology and the Hebrew Bible