This Bible contradiction is from the Skeptic's Annotated Bible.
Joshua 21:23-24 View context
And out of the tribe of Dan, Eltekeh with her suburbs, Gibbethon with her suburbs,
Aijalon with her suburbs, Gath-rimmon with her suburbs; four cities.
1 Chronicles 6:66 View context
And [the residue] of the families of the sons of Kohath had cities of their coasts out of the tribe of Ephraim.