We reported microscopic pK a s for all ionizable groups we identified in the SAMPL6 molecules. The first step for any prediction we perform is to identify ionizable groups and then iterate through those groups to find all microscopic transitions. For SAMPL6, all resonance structures of a given microstate were considered to be a single state and assigned a single identification number for the set. We matched each molecular microstate to the proper identification number using a script adapted from the SAMPL6 organizers that identifies identical resonance structures. A full table of microscopic pK a s and the script used to find their identification numbers is provided in the supplementary information.