A peninsula is a landform that is surrounded by water on three sides but remains connected to the mainland on one side. This geographical feature often extends into a body of water, such as an ocean, sea, or lake, and can vary in size from small to large. Peninsulas can provide unique ecosystems and are often significant in terms of human settlement and development due to their access to marine resources and transportation routes. Examples include the Iberian Peninsula in Europe and the Florida Peninsula in the United States.

Several states in the U.S. have peninsulas, but Michigan is the most notable example, as it is divided into two peninsulas: the Upper Peninsula and the Lower Peninsula. The state is surrounded by the Great Lakes, which contribute to its distinct geography. Other states with notable peninsulas include Florida (with the Florida Keys and the Pinellas Peninsula) and Washington (with the Kitsap Peninsula). Each of these areas features unique landscapes and ecosystems, influenced by their coastal locations.

New Jersey is not a peninsula; it is a state located on the eastern coast of the United States. However, it is bordered by water on three sides: the Atlantic Ocean to the south and east, and the Hudson River and Upper New York Bay to the north. The term "peninsula" refers to a landmass surrounded by water on three sides, and while New Jersey has some peninsular areas, the state itself is not classified as a peninsula. The movie "Peninsula" is a sequel to "Train to Busan" and is set in a post-apocalyptic world, but it does not directly relate to geographical definitions.

In a kitchen, a "peninsula" refers to a countertop extension that is connected to a wall or another surface on one side, while the other side is open for accessibility. It typically serves as an additional workspace, dining area, or a place for appliances, and is often used to create a more functional layout in open-plan kitchens. The design promotes interaction and can enhance the flow of the kitchen, making it a popular choice in modern kitchen designs.