Stock Island is a census-designated place (CDP) and unincorporated community on an island of the same name in Monroe County, Florida, United States. The population of the CDP was 4,722 at the 2020 census, up from 3,919 in 2010. It is located on the portion of the island south of US 1. It is supposedly named for the herds of livestock formerly kept there. Alternatively, some local historians suggest that it may be named for an early settler. Geography Stock Island is located at (24.570075, -81.737376). US 1 (or the Overseas Highway) crosses the key at approximately mile markers 4–6, immediately east of Key West. According to the United States Census Bureau, the CDP has a total area of , of which are land and , or 60.24%, are water. Demographics 2020 census As of the 2020 United States census, there were 4,722 people, 1,584 households, and 1,081 families residing in the CDP. 2000 census As of the census of 2000, there were 4,410 people, 1,713 households, and 1,050 families residing in the CDP. The population density was 1,891.9/km (4,919.1/mi2). There were 1,855 housing units at an average density of 795.8/km (2,069.2/mi2). The racial makeup of the CDP was 79.95% White, 10.45% African American, 0.36% Native American, 1.09% Asian, 0.05% Pacific Islander, 4.76% from other races, and 3.33% from two or more races. Hispanic or Latino of any race were 43.33% of the population. There were 1,713 households, out of which 29.6% had children under the age of 18 living with them, 39.5% were married couples living together, 15.4% had a female householder with no husband present, and 38.7% were non-families. 26.0% of all households were made up of individuals, and 5.4% had someone living alone who was 65 years of age or older. The average household size was 2.57 and the average family size was 3.12. In the CDP, the population was spread out, with 23.5% under the age of 18, 8.3% from 18 to 24, 33.2% from 25 to 44, 26.5% from 45 to 64, and 8.5% who were 65 years of age or older. The median age was 37 years. For every 100 females, there were 118.6 males. For every 100 females age 18 and over, there were 118.8 males. The median income for a household in the CDP was $31,537, and the median income for a family was $38,029. Males had a median income of $23,714