Time series techniques were employed to determine rates of vertical crustal movement within the Great Lakes region of North America. Observations of water level elevations as recorded at gauges around the lakes, and differences in elevations between pairs of gauges were analysed for linear trends, periodicities and stochastic components. It was found that the variance of time series of elevations consisted mainly of first-order linear trends and small periodic components. Relative rates of crustal movement were computed from a linear trends analysis of elevation differences. These rates were converted to absolute rates of movement using the Nipissing zero isobase as a datum. This study shows that, in general, the northeastern area of the Great Lakes region is rising at a rate of about 1·00 ft per 100 years relative to the southwest of the region.