Coastal environments of Humboldt County provide an optimal habitat for a diversity of macroinvertebrates. This study’s focus is to determine the differences in diversity of coastal macroinvertebrate (CM) species on intertidal boulders. Eleven CM species were visually counted within a one-square-meter quadrat along two height strata of five intertidal boulders. Based upon the Shannon-Wiener diversity index, diversity was measured between the CM species in the lower region (0-1 meter from base of boulder) and the upper region (1-2 meters from base of boulder). The resulting data showed the lower regions of the boulders had a higher average diversity rating, as compared to the upper boulder regions