Only 0.7% of 28,205 known New England ant specimens (1861–2011) were from Rhode Island. Consequently, apparent ant species richness of Rhode Island counties was lower than expected based on simple biogeographic models. Collections from two poorly sampled areas—Block Island and Tiverton—and from the 2013 Rhode Island Natural History Survey's BioBlitz increased Rhode Island's ant specimens by 46%) and its ant species richness from 48 to 57. Both Washington and Newport counties now have ant species richness more in line with New England-wide species-environment predictions. The extrapolated number of Rhode Island ant species is 66, but the upper bound of the 95% confidence interval is 93 species and the total species accumulation curve has not reached an asymptote. Future collection efforts should continue to add ant species to the Rhode Island list, especially if collections are targeted in the state's north and southeast regions, and its southwest pine barrens.