Being in the sphere of influence of other cities can have benefits as it allows cities to “borrow size,” but this can also lead to competition effects known as “agglomeration shadows.” This paper examines how these patterns of borrowing and shadowing differ from domestic settings when there is a national border between the cities. We find that borders moderate the normal regularities of a settlement system. Particularly, there is no shadow effect cast by larger cities across borders; borders protect. Cross-border market integration benefits especially similar-sized border cities. Given these unique advantages, it is time for border cities to step out of the shadows.