For all cities with a population greater than five hundred thousand, Slough is closest to London and farthest from Auckland. The closest foreign city is Rotterdam and the farthest domestic city is Glasgow. See below for the top 5 closest and farthest cities (domestically, internationally and by continent) and to see which cities, if any, Slough is the closest and farthest to. Filter to include all cities over 100k, 500k or 1 million in population.