Metric System
100 sq mm 1 sq cm
10,000 centimeters 1 sq m
100 sq meters 1 are (a)
100 ares 1 hectare
100 hectares 1 sq km
U.S. System
144 sq inches 1 sq ft
9 sq feet 1 sq yard = 1296 sq in
30 1/4 sq yards 1 sq rod = 272 1/4 sq ft
160 sq rods 1 acre = 4,840 sq yds
640 acres 1 sq mile
1 sq mile 1 section
6 sq miles 1 township = 36 sections