Aptostichus stephencolberti is distributed throughout the coastal dune habitats of San Francisco, San Mateo, Santa Cruz, and Monterey Counties with a single population recorded from San Luis Obispo County (Map 4). Individuals are found in relatively deep burrows on the steep faces of sand dunes and at the base of coastal vegetation. Burrows comprise a thick silk lining and are covered by a very cryptic trapdoor constructed of silk and sand. Dune habitats disturbed by high concentrations of the invasive Carpobrotus edulis (ice plant) tend to lack Aptostichus stephencolberti individuals entirely. The DM for this species (Map 5) follows closely with the known distribution to include the southernmost-recorded locality for the species. Wandering males (2) have been collected in August and September; two males have been collected from burrows in January.