is a city in Collier County, Florida, United States. The city is an island on the Gulf of Mexico off the coast of Southwest Florida. It is a principal city of the Naples–Marco Island Metropolitan Statistical Area. The population varies from approximately 15,791 full time residents to 35,000 during height of vacation season.
Marco Island is the largest barrier island within Southwest Florida's Ten Thousand Islands area extending southerly to Cape Sable. The climate is subtropical with distinct wet and dry seasons with most of the rainfall falling between the months of June and October.
As of the census of 2000, there were 12,879 people, 4,134 households, and 2,200 families residing in the city. The population density was 943.5/km² (1,407.1/mi²). There were 10,826 housing units at an average density of 841.6/km² (1,402.1/mi²). The racial makeup of the city was 94.1% White, 4.1% Hispanic or Latino, 0.6% Asian, 0.2% African American, 0.02% Native America, 0.5% from other races, and 0.4% from two or more races.
The median income for a household on the island was $60,357, and the median income for a family was $68,979. Males had a median income of $39,651 versus $26,460 for females. The per capita income for the city was $42,875. About 4.3% of families and 10.0% of the population were below the poverty line, including 4.4% of those age 65 or over.