From 1902–2005 six species of Nolidae, 88 species of Erebidae, and 118 species of Noctuidae have been recorded from Plummers Island, Montgomery County, Maryland. Extensive collecting conducted from 1998–2005 resulted in five species of Nolidae, 70 species of Erebidae, and 88 species of Noctuidae. Only the Nolidae had sufficient specimens collected from 1902–1930 to compare with collections taken from 1998–2005. Five species were present from 1902–1930, and five from 1998–2005 with no change in species richness. A 20% species turnover was noted, with one extinction and one colonization. Owing to probable under-sampling from 1902–1930, the Erebidae and Noctuidae show a 37% and a 32% increase, respectively. This is contrary to other studies at Plummers Island, which showed a decrease in species richness. Species accumulation curves were based only on material collected from 1998–2005. Both abundance and incidence-based estimators were used to predict six species of Nolidae, 79–102 species of Erebidae, and 101–135 species of Noctuidae. Of the total of 212 species for all three families, 75.9% of the species were represented by 10 or fewer specimens. A checklist of the Nolidae, Erebidae, and Noctuidae, and their monthly abundances from 1902–2005 is provided.