Mark-release-recapture studies were conducted to estimate foraging populations, maximum foraging distances between foraging sites, and minimum total foraging distance for three colonies of two cuticular hydrocarbon phenotypes of Reticulitermes at a wildland site near Placerville, CA, in the Sierra Nevada foothills and for six colonies of three phenotypes at two residential sites in Marin County. At Placerville, the hydrocarbon phenotype B colony had the fewest termites, with an estimated foraging population of 4,476–13,602, and occupied only one monitoring station. The two phenotype A colonies had foraging populations estimated to range from 40,809 to 128,597; one inhabited one monitoring station, whereas the other occupied three stations with a maximum distance between monitoring stations of 6.3 m. At the Marin County sites, two phenotype D colonies were estimated to have foraging populations ranging from 9,191 to 194,692; each foraged at a single monitoring station. Estimated foraging populations for the three phenotype A′ colonies ranged from 71,483 to 491,901 with the maximum distance between monitoring stations ranging from 11.7 to 25.3 m. The phenotype A colony was estimated to have 8,747–25,190 foragers, with a maximum distance between monitoring stations of 1.8 m.