Big Pine Key is a census-designated place and unincorporated community in Monroe County, Florida, United States, on an island of the same name in the Florida Keys. As of the 2020 census, the town had a total population of 4,521. Geography U.S. 1 (the Overseas Highway) crosses the key at mile markers 29.5–33, one of the few places on the keys where the road orients north–south (along the eastern edge of the Key). The highway leads west-southwest to Key West and east-northeast to Marathon. Big Pine Key was the location of one of the stations of the Overseas Railroad. According to the United States Census Bureau, the CDP has a total area of , of which , or 1.04%, is covered by water. Demographics 2020 census As of the 2020 United States census, there were 4,521 people, 2,065 households, and 1,180 families residing in the CDP. 2000 census As of the census of 2000, 5,032 people, 2,247 households, and 1,420 families resided in the CDP. The population density was 198.9/km (515.3/mi2). The 3,153 housing units averaged 124.6/km (322.9/mi2). The racial makeup of the CDP was 94.83% White, 1.09% African American, 0.50% Native American, 0.58% Asian, 0.02% Pacific Islander, 1.19% from other races, and 1.79% from two or more races. Hispanics or Latinos of any race were 6.72% of the population. Of the 2,247 households, 41.4% had children under the age of 18 living with them, 43.8% were married couples living together, 5.7% had a female householder with no husband present, and 6.8% were not families. About 26.0% of all households were made up of individuals, and 7.8% had someone living alone who was 65 years of age or older. The average household size was 2.21 and the average family size was 2.63. In the CDP, the population was distributed as 16.8% under the age of 18, 4.3% from 18 to 24, 30.3% from 25 to 44, 33.7% from 45 to 64, and 14.9% who were 65 years of age or older. The median age was 44 years. For every 100 females, there were 110.4 males. For every 100 females age 18 and over, there were 111.6 males. The median income for a household in the CDP was $44,514, and for a family was $47,639. Males had a median income of $31,552 versus $28,021 for females. The per capita income for the CDP was $23,169. About 5.6% of families and 9.5%