Siesta Key is a barrier island off the southwestern coast of Florida in the United States. It is situated between Roberts Bay and the Gulf of Mexico. A portion of it lies within the city boundary of Sarasota, but the majority of the key is a census-designated place (CDP) in Sarasota County. After the probable Amerindian name of Zarazote for the area and the bay, the key was originally named "Sarasota Key" by European cartographers during exploration beginning in 1513.