OK - Leeds most Northern City left in the FA Cup:
Burnley FC is the most northerly club left in the FA Cup, Leeds is the most northely town or city with a team left in the FA Cup.
According to the World Geodetic System Turfmoor lies 53 degrees 47' 21'' N, Elland Road is 53 degrees 46'' 40'' N
Burnley however is apparently 53 degrees 47' 20.4'' N, slightly south of Leeds at 53 degrees 47' 59'' N