The Florida Panhandle (also called Northwest Florida) is the 200-mile strip stretching from the Alabama border to the Apalachicola River. Its name is purely geographic.
Imagine a frying pan:
This "handle" is bordered by Alabama (north), Georgia (northeast), and the Gulf of Mexico (south).
In the mid-1800s, the U.S. government opened these lands (ceded by Creek/Seminole treaties) for homesteading. Settlers rushed to claim 160-acre parcels—echoing the Oklahoma Land Runs. The term "Panhandle" gained currency during this period.
The Panhandle is more "Deep South" than peninsular Florida: slower pace, stronger Southern drawl, less Latino influence, dominant Baptist/Methodist churches, economy tied to military (Eglin, Hurlburt, Pensacola NAS), forestry, and tourism.