A molecular field theory (MFT) developed by the author [Phys. Rev. Lett. 109, 077201 (2012); Phys. Rev. B 91, 064427 (2015)] has been used in the past to fit single-crystal magnetic susceptibility χ versus temperature T data below the antiferromagnetic ordering temperature TN for a variety of collinear and coplanar noncollinear Heisenberg antiferromagnets. The spins in the system are assumed to interact by Heisenberg exchange and to be identical and crystallographically equivalent. The fitting parameters for χ(T ) of collinear antiferromagnets are measurable quantities: the Weiss temperature θp in the Curie-Weiss law, TN, χ(TN), and the spin S. For coplanar noncollinear helix and cycloid structures, an additional fitting parameter is the turn angle between layers of ferromagnetically-aligned spins. Here MFT fits to anisotropic χ(T ) data from the literature for single crystals of the collinear antiferromagnet CuO and the noncollinear antiferromagnets LiCrO2 with a 120 • cycloidal structure and α-CaCr2O4 with a 120 • helical structure below their respective Néel temperatures are presented. The MFT fit to the anisotropic χ(T ≤ TN) data for CuO is poor, whereas the fits to the data for LiCrO2 and α-CaCr2O4 are quite good. The magnetic contribution to the zero-field heat capacity of the collinear antiferromagnet GdCu2Si2 is also fitted by the MFT.