Treasure Island is a city in Pinellas County, Florida, United States. It is situated on a barrier island in the Gulf of Mexico. As of the 2020 census, the city population was 6,584. Geography According to the U.S. Census Bureau, the city has a total area of 5.3 square miles (13.8 km), of which 1.6 square miles (4.1 km) is land and 3.7 square miles (9.7 km) (70.11%) is water. Demographics At the 2000 census there were 7,450 people in 4,128 households, including 2,059 families, in the city. The population density was . There were 5,694 housing units at an average density of . The racial makeup of the city was 97.69% White, 0.28% African American, 0.28% Native American, 0.59% Asian, 0.03% Pacific Islander, 0.43% from other races, and 0.70% from two or more races. Hispanic or Latino residents of any race were 2.23%. Of the 4,128 households 10.0% had children under the age of 18 living with them, 43.8% were married couples living together, 4.2% had a female householder with no husband present, and 50.1% were non-families. 41.5% of households were one person and 14.3% were one person aged 65 or older. The average household size was 1.80 and the average family size was 2.38. The age distribution was 9.2% under the age of 18, 2.7% from 18 to 24, 23.4% from 25 to 44, 38.5% from 45 to 64, and 26.3% 65 or older. The median age was 52 years. For every 100 females, there were 95.8 males. For every 100 females age 18 and over, there were 95.0 males. The median household income was $42,150 and the median family income was $64,158. Males had a median income of $38,903 versus $32,586 for females. The per capita income for the city was $34,965. About 3.9% of families and 5.6% of the population were below the poverty line, including 0.4% of those under age 18 and 6.9% of those age 65 or over. History The area of Treasure Island was originally settled in small communities by the Tocobaga around 300 CE. The Timucua traded with other Native American tribes in the area until the arrival of Pánfilo de Narváez in 1528. De Narváez decimated the indigenous people before leaving the area in search of gold. Treasure Island got its name early in the 20th century, after several property owners attempted to boost sales of the properties being developed on