In 2022, the population of Cusick was 159, a 2.58% increase year-by-year from 2021. Previously, in 2021, Cusick's population was 155, an increase of 2.65% compared to a population of 151 in 2020.
The median age in Cusick, WA is 54.2, as per 2021 ACS 5-Year Estimates. Of the total population, 11.43% were under the age of 15, 18.57% aged 15 to 29, 62.86% aged 30 to 64, 7.14% aged 65 to 84, and 0.00% were 85 years of age and older.