We study the US city size distribution over space. This paper makes two contributions to the empirical literature on city size distributions. First, this study uses data from different definitions of US cities in 2010 to study the distribution of cities in space, finding significant patterns of dispersion depending on city size. Second, the paper proposes a new distance-based approach to analyse the influence of distance on the city size distribution parameters, considering both the Pareto and lognormal distributions. By using all possible combinations of cities within a 300-mile radius, results indicate that the Pareto distribution cannot be rejected in most of the cases regardless of city size. Placebo regressions validate our results, thereby confirming the significant effect of geography on the Pareto exponent.