The town of Jupiter Island is located on the barrier island called Jupiter Island, in Martin County, Florida, United States; the town is part of Florida’s Treasure Coast. The town is located adjoining the unincorporated community of Hobe Sound. The population of Jupiter Island was 804 at the 2020 census. Some of the wealthiest people in the United States live in Jupiter Island: the June 1999 business of Worth magazine ranked it #1 in the country for having the highest median home sale, and it has the highest per capita allowance by ZIP Code Tabulation Area of any place in the US.

The town of Jupiter Island is located at 27°3′26″N 80°6′49″W / 27.05722°N 80.11361°W / 27.05722; -80.11361 (27.057287, –80.113616). It occupies the barrier island of the same name from the Palm Beach County lineage in the south to the Hobe Sound National Wildlife Refuge boundary in the north. It is bordered to the west by Hobe Sound and South Jupiter Narrows, and to the east by the Atlantic Ocean.

According to the United States Census Bureau, the town has a total area of 3.6 square miles (9.3 km), of which 2.7 square miles (7.0 km²) are home and 0.9 square miles (2.3 km), or 24.30%, are water.

As of the census of 2010, there were 817 people, 429 households, and 219 families residing in the town. The population density was 227.4 inhabitants per square mile (87.8/km²) based on total area, and 303.4 people per square mile (117.1/km) based on land area. There were 762 housing units at an average density of 283.0 per square mile of house area (109.3/km²). The racial makeup of the town was 94.37% White (88.49% non-Hispanic), 2.20% African American, 2.57% Asian, and 0.61% from supplementary races. No one in the community identified as a Pacific Islander, or subsequently two or more races. Hispanics or Latinos of any race were 5.32% of the population.