In[]:=
tokyoCoords=GeoPosition[CityData[{"Tokyo","Tokyo","Japan"}]];​​ent=EntityValue
United States
COUNTRY
;​​fullCoords=Flatten[ent["FullCoordinates"],1];(*iwasn'tsurewhythepointswheregroupedthewaytheywere.IthinkIjustwantarawlistofGeoPosition[]pointssothat'swhyIflattenittolevel1*)​​USEdges=GeoPosition[{#1,#2}]&@@@fullCoords;​​GeoGraphics[USEdges]​​
Out[]=
​
In[]:=
dists=GeoDistance[USEdges,tokyoCoords]//Normal;​​minPt=USEdges[[First@Ordering@dists]]​​GeoGraphics[GeoMarker[minPt],GeoRangeQuantity[1500,"Miles"]]​​
Out[]=
GeoPosition[{20.5515,144.889}]
Out[]=