A new local curve of relative sea-level change for the Delaware coastal area is based on 88 radiocarbon dates. The curve is smooth with relatively narrow potential limits of variation in amplitude. It has a somewhat steeper slope than published eustatic sea-level curves and other local relative sea-level curves. Holocene radiocarbon isochrons in Delaware marsh sections are horizontal. Interpretations strongly support the concept that Holocene sea level rose slowly and continuously relative to the Delaware coast; the favored hypothesis is that eustatic rise of sea level was responsible. No seaward tilting is indicated for the Delaware segment of the Atlantic coastal plain or inner shelf. However, radiocarbon-died shallow-water samples of comparable age suggest a strong seaward tilt of the outer continental shelf. The outer shelf over the Baltimore Canyon trough geosyncline has subsided approximately 40 m in the last 10,000 years.