The areal distribution of the benthic alga Cladophora glomerata and the percent areal coverage of Cladophora within 45.8 m (150 ft) by 15.3 m (50 ft) model cells for a 2.8 km length of Lake Huron shoreline at Harbor Beach, Michigan, are determined by remote sensing techniques. Data were acquired on 21 July 1979, a calm, clear day over Lake Huron at an altitude of 305 m with an eleven-channel modular multispectral scanner mounted in a NASA C-131 aircraft. Cladopora is determined by a conventional maximum likelihood statistical supervised classification technique employing three of the scanner bands. An intensive field survey of the study site indicated that the computer classified imagery is representative of the Cladophora distribution at Harbor Beach.