These data include the general extents of canopy-forming kelp surveys from 1989 to 2014 and a compilation of existing data sets delineating canopy-forming kelp beds along the coasts of Washington, Oregon, and California. Canopy-forming kelp includes species of the genera Nereocystis (bull kelp) and Macrocystis (giant kelp). It does not include the understory kelp genera, such as Laminaria or Alaria. The source data were created from remote-sensing surveys (aerial photos and digital imagery) which often used different survey methods from area to area or year to year. The data depict all kelp observations from all surveys, merged into continuous polygons with the internal boundaries removed (dissolved). This depiction is sometimes referred to as the "maximum extent." Different sections of the coast have been surveyed during different time periods. The number of surveys per section of coast ranges from 1 to 25 surveys. The kelp survey extent data depict the general sections of coastline that were surveyed, how many times they were surveyed, the years of the survey, and which source data were included in the final kelp data compilation.