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 For statistical purposes, the United States Census Bureau has defined Seacliff as a census-designated place (CDP). The census definition of the area may not precisely correspond to local understanding of the area with the same name. The 2010 United States census reported Seacliff's population was 3,267. Geography According to the United States Census Bureau, the CDP covers an area of 0.8 square miles (2.0 km), 99.90% of it land and 0.10% of it water. Seacliff sits at an elevation of . The 2010 United States census reported Seacliff's population was 3,267. Demographics The 2010 United States Census reported that Seacliff had a population of 3,267. The population density was . The racial makeup of Seacliff was 2,758 (84.4%) White, 28 (0.9%) African American, 40 (1.2%) Native American, 100 (3.1%) Asian, 4 (0.1%) Pacific Islander, 189 (5.8%) from other races, and 148 (4.5%) from two or more races. Hispanic or Latino of any race were 482 persons (14.8%). The Census reported that 3,267 people (100% of the population) lived in households, 0 (0%) lived in non-institutionalized group quarters, and 0 (0%) were institutionalized. There were 1,536 households, out of which 354 (23.0%) had children under the age of 18 living in them, 551 (35.9%) were opposite-sex married couples living together, 184 (12.0%) had a female householder with no husband present, 76 (4.9%) had a male householder with no wife present. There were 135 (8.8%) unmarried opposite-sex partnerships, and 34 (2.2%) same-sex married couples or partnerships. 504 households (32.8%) were made up of individuals, and 142 (9.2%) had someone living alone who was 65 years of age or older. The average household size was 2.13. There were 811 families (52.8% of all households); the average family size was 2.67. The population was spread out, with 553 people (16.9%) under the age of 18, 279 people (8.5%) aged 18 to 24, 868 people (26.6%) aged 25 to 44, 1,150 people