A hydrographic survey of 286 CTD stations was made in May 1977 in the region between 37 ¿N (i.e., near San Francisco) and 43 ¿N (i.e., Cape Blanco in southern Oregon). Coastal upwelling was most intense south of Cape Mendocino. At 300 m an intense temperature and salinity frontal zone occured between 38 ¿N and 39 ¿N. The dynamic height topographies 0/900 dbar and 300/900 dbar contained regions of highs and lows with length scales of 100--150 km. North of Cape Mendocino the warm saline water identified as the poleward California Undercurrent was not observed, and the transport integrated above 900 dbar was southward.