Sanibel is an island and city in Lee County, Florida, United States. The population was 6,469 at the 2010 census, with an estimated 2018 population of 7,402. It is part of the Cape Coral-Fort Myers, Florida Metropolitan Statistical Area. The island, also known as Sanibel Island, constitutes the entire city. It is a barrier island – a collection of sand on the leeward side of the more solid coral-rock of Pine Island.
Most of the city proper is at the east end of the island. After the Sanibel causeway was built to replace the ferry in May 1963, the city was incorporated in 1974 and the residents asserted control over development by establishing the Sanibel Comprehensive Land Use Plan, helping to maintain a balance between development and preservation of the island's ecology.
Due to easy causeway access, Sanibel is a popular tourist destination known for its shell beaches and wildlife refuges. More than half of the island is made up of wildlife refuges, the largest being J. N. "Ding" Darling National Wildlife Refuge. The Island hosts the Sanibel Historical Village and a variety of other museums including the Bailey-Matthews National Shell Museum and theaters, as well as many non-profit organizations such as the Sanibel-Captiva Conservation Foundation, the Clinic for the Rehabilitation of Wildlife, and the Sanibel Sea School.