Casselberry is a city in Seminole County, Florida, United States. The population was 26,241 at the 2010 census.  The city is usually considered linked to the OrlandoKissimmeeSanford Metropolitan Statistical Area. According to the United States Census Bureau, the city has a total area of 7.1 square miles (18km2). 6.7 square miles (17km2) of it is land and 0.4 square miles (1.0km2) of it (6.06%) is water. However, "Where is Casselberry?" is more a common question than one might think. These are the municipal boundaries, and they have extended from years of annexation into other areas that were previously unincorporated Seminole County. Addresses carry the name of the city handling the mail, not necessarily the name of the city in which the property is located. In certain instances, "Casselberry" is actually known as Maitland, Winter Park, and Winter Springs. Likewise, some parts of what is called Casselberry do not lie within the city. Casselberry features over 30 lakes and ponds, the largest being Lake Howell, the Triplet Chain of Lakes, Lake Kathryn, and Lake Concord.