Dispersed high‐order modes have been observed at frequencies as high as 300 Hz and at ranges of 600 km for shots detonated and received on the axis of a SOFAR channel located in the western Mediterranean Sea. Spectrum analysis of shot records has revealed as many as five identifiable group‐velocity profiles that correlate with modes as high as 70. Accurate prediction of observed group‐velocity profiles is obtained by applying WKB mode theory to sound‐velocity data. In addition, dispersion of individual resolved multipath arrivals, for which low frequencies tend to arrive later, is observed and analyzed by a modified ray theory including diffraction effects.