We collected 1850 km of ground-based radio echo-sounding (RES) data in West Antarctica along the 2001 US leg of the International Trans-Antarctic Scientific Expedition traverse (US-ITASE). These data represent the first high-resolution measurements of ice thickness and internal stratigraphy for portions of this area that bear on questions about the stability of the West Antarctic Ice Sheet (WAIS). Internal layers depicting isochrones have been traced continuously for much of the profile length and a date from the Byrd Deep Core is ascribed to one of these isochrones from which we estimate vertical velocities across the traverse route. Comparison of our ice thickness measurements with BEDMAP show good agreement in regions where the database is well constrained by data coverage. Where the BEDMAP dataset was forced to interpolate, differences are as high as 45% of the ice thickness.