With regard to the most common answer, Florida is the state that can most commonly be referred to as a true peninsula.
Only a few of the US states are actually peninsulas (surrounded by three sides of water) the most obvious answer is Florida, but many forget that lakes are also large bodies of water and the Great Lakes surround the state of Michigan. Finally the great state of Alaska is overlooked often because it is forgotten compared to the lower 48, and when one thinks about it, the Arctic Ocean to the North and The Pacific to the south and west, it is also a giant peninsula.
To consider but really not included in this answer:
Many states have portions of their state which are peninsulas. California has many peninsulas (San Francisco), Washington, Massachusetts, all have large peninsulas within their state, as well as New Jersey.
One state which may be considered by few to be a peninsula entirely is Louisiana. Water to the east, west, and south.
The Three U.S states that are peninsulas are Alaska, Michigan, and Florida
The following states are geographically expected to be peninsulas:Florida & Michigan.
14 peninsulas
Chicago,IL
They are both states, peninsulas, and both were purchased from Another Country.
Peninsulas are pieces of land that are surrounded by water but connected to mainland via an isthmus. States that could be peninsulas: -Alaska -Florida -New Jersey (There are many other states that are peninsulas or have peninsulas on them, such as New York, Utah, Michigan, California, and Virginia)
There are simply just 14 peninsulas. :} :]
All of Europe is a peninsula of peninsulas. This is because Europe is a peninsula itself, and contains many, many peninsulas.
Massachutes, Florida, and Alaska. I think. Michigan comprises two peninsulas; Mass. none.
The link below, Peninsulas of the World, may be some help to you.
Michigan
mexico