The book takes place sometime during the period of the judges, probably around 1200 B.C .The book begins" Now it came to pass in the days when the judges governed. . ."
However, it probably was not written down until sometime later, possibly anywhere from 1375 B.C to 450 B.C. In Ruth 4:6,7, the writer must explain some of the customs when the book take place. This would suggest that some time has elapsed between the actual story and the time in which it was put in written form. The book also contains references to King David which might put its authorship as early as 1000 B.C.
The setting takes place in both Moab, which today is part of modern day Jordan, and Israel/Palestine, specifically the area around Bethlehem. The geography was probably similar to today. The major problem at the beginning of the book is a famine in Israel. A man named Elimelech takes his wife Naomi and their sons out of Bethlehem in Israel and goes Moab to escape the famine.