Three-dimensional lightning mapping observations from the Oklahoma Lightning Mapping Array (OK-LMA) were used to analyze charge structure of a splitting supercell on 26 May 2004 during the Thunderstorm Electrification and Lightning Experiment (TELEX). The OK-LMA was used to evaluate cloud-to-ground (CG) flashes reported by the National Lightning Detection Network’s (NLDN). Each NLDN flash between 2300 UTC and 2310 UTC was classified as either a CG or an intra-cloud (IC) flash using LMA-inferred charge structure. The LMA analysis of the charge structure supports charge structure for 23% of the positive CGs. Most of the negative NLDN flashes that were analyzed were not confirmed by the LMA.