Seacliff is an unincorporated community in Santa Cruz County, California, United States that includes Seacliff State Beach. It is identified as one of several small communities with a combined population of 24,402 forming the unincorporated town of Aptos by the local Chamber of Commerce along with:Aptos Hills-Larkin Valley, a rural area north of State Route 1 Cabrillo Rio Del Mar, south of State Route 1, from Aptos Creek southeast to Seascape Seascape, south of State Route 1, centered on Seascape Beach Resort