Nest and chick census data gathered from 1975–2005 at all known breeding colonies of Royal (Sterna maxima) and Sandwich (S. sandivicensis) Terns in three mid-Atlantic States are reported. Nest census data were gathered sporadically in North Carolina, Virginia, and Maryland throughout this period. Royal Tern chick counts based on annual banding efforts were obtained in Maryland since 1975 and North Carolina and Virginia since 1977, while Sandwich Tern chick counts date from 1977 in North Carolina and 1980 in Virginia. Royal Tern chick counts show significant annual variation by state, and are positively correlated between North Carolina and Virginia, but negatively correlated between Maryland and both North Carolina and Virginia. Sandwich Tern nest counts showed significant annual variation in North Carolina, as did chick counts in North Carolina and Virginia. These results suggest regional, rather than local, trends in Royal Tern numbers over time. While Royal Tern numbers indicate a gradual decline in nests and chick production since the 1980s, followed by an increase in recent years, Sandwich Tern numbers have remained consistently lower than Royal Terns but stable over the entire study period. Causes for the decline in Royal Tern numbers are attributed primarily to loss of open sandy habitat from vegetational succession at breeding sites on dredged material islands and to invasive species at nesting sites, including quadraped predators. Increased habitat management and regular censusing with consistent methodology are recommended to help maintain these species at sustainable levels.