Chromosome numbers are reported for 53 individuals of 10 species of Solidago L. sect. Maritimae (Torr. & A. Gray) Semple & Beck from eastern Canada and the eastern United States: S. austrina Small, S. chrysopsis Small, S. gracillima Torr. & A. Gray, S. mexicana L., S. pulchra Small, S. sempervirens L., S. simulans Fernald, S. stricta Aiton, S. uliginosa Nutt., and S. virgata Michx. Identifications of nearly all vouchers for 262 previously published counts for the section were confirmed or revised following the treatments of the section by Semple et al. No counts have been reported for the Mexican species S. maya Semple and S. paniculata DC. and for S. uliginosa var. terra-novae (Torr. & A. Gray) Fernald from Newfoundland. Polyploids are documented in six of the 13 species: S. austrina, S. mexicana, S. pulchra, S. stricta, S. uliginosa, and S. virgata. In addition, we provide the first chromosome count for S. chrysopsis (2n = 18) from Florida. All 315 count reports from 231 locations were used to map the cytogeography of all species in the section.