Calculations using an extended basis set and the Becke 3-parameter exchange functional and Perdew 86 correlation functional are used to predict the geometry and isotropic hyperfine coupling constants for Mg-n(+) clusters (n less than or equal to 6). The Mg-3(+) results agree with our previous MRSDCI results and disagree with another recent DFT calculation. For n=4 and 5, our results agree with previous work. For n=6, we obtain a trapezoid-based bipyramid that was not considered in any previous papers. Based on these calculations, we are able to rationalize the experimental hyperfine couplings.