The properties of a two-dimensional geometrically frustrated magnetic material based on the Kagomé net, Ba 2 Sn 2 ZnGa 3 Cr 7 O 22, are reported. The Kagomé net is fully filled with magnetic ions. A Curie-Weiss theta θ W=− 312 K is found with a spin glass transition at approximately 1.5 K, indicating strong geometrical magnetic frustration. This compound is the most two dimensional of a structural series with the geometrically frustrated materials ZnCr 2 O 4 and SrCr 8 Ga 4 O 19. The comparison of their properties tests the influence of different degrees of coupling between Kagomé layers on magnetic frustration within a single chemical and structural family.