Perhaps it hasn't ever struck you as odd, but to me it is strange that God originally made this planet all rural (beginning with the Garden of Eden) but has called a people unto Himself and to His city (Hebrews 11:10 & 16). In my very limited experience it seems that cities are generally the bastions of evil while more conservative family values and traditional morals are preserved out where the stars can still be seen.
Regardless of my perceptions though, this was God's program for the Jews. The Levites were given 48 cities throughout the nation. Now, 6 of them (and their suburbs) were set aside for the Levites to inhabit for the preservation of a proper balance between mercy and justice. God ordained 3 cities for the 9 tribes on the west side and 3 for the 2 tribes on the east side (for the safety of men guilty of unintentional manslaughter and for any man who claimed innocence ... until he could stand trial - see Numbers 35:12). Thus the cities were spread out geographically so as to make them accessible with relative ease from anywhere in the nation.