Sorry Michigan, But Your Lower Peninsula Is Smaller Than You Think and Your Upper Peninsula Is a Figment of the Imagination

A peninsula, Wikipedia tells us, “is a landform that extends from a mainland and is surrounded by water on most sides.Any body of water can count, the article claims, including rivers: “A piece of land on a very tight river bend or one between two rivers is sometimes said to form a peninsula. …” In practice, however, the inclusion of rivers occurs only at the local scale; a large extent of land bracketed by rivers is almost never called a peninsula, and for good reasons. Consider, for example, Mesopotamia, which is almost entirely “surrounded” by the Tigris and Euphrates rivers. Does it “extend from a mainland?” Is it ever depicted as a peninsula? An internet search returned exactly one instance of this usage, an article by Turkish authors on the “Vernacular Domed Houses of Harran, Turkey.” Perhaps they are not familiar with the vernacular definition of the world “peninsula” in English. Following such usage, ChatGPT insists that “Mesopotamia” is not a peninsula.


ChatGPT 3.5: “Mesopotamia is not a peninsula. It’s actually considered one of the world’s earliest civilizations, located in the region between the Tigris and Euphrates rivers, which is in present-day Iraq and parts of Syria, Turkey, and Iran. While it’s bordered by water, it’s not surrounded by water on three sides like a peninsula would be. Instead, it’s known as a river valley civilization due to its location between these two major rivers.

(Unfortunately, the chatbot’s answer is not fully coherent: “Mesopotamia” was the location of “one of the world’s earliest civilizations,” not the civilization itself, and it was definitely “surrounded by water on three sides,” at least if one counts flowing water in the definition of the term.)

But in Great Lakes region straddling the border between the United States and Canada the vernacular English definition of the word “peninsula” vanishes. Three large peninsulas are distinguished in this area: Michigan’s Upper Peninsula, Michigan’s Lower Peninsula, and Ontario Peninsula. All three appear prominently on political maps, but this is essentially an artifact of the division between the two countries. A non-political depiction of large water bodies in this region reveals only one large peninsula, the Lower Peninsula of Michigan, and it is not as large as it is conventionally imagined. The Upper Peninsula of Michigan and Ontario Peninsula are evident only if exaggerates the size of rivers and counts them as water bodies separating peninsulas from mainland areas. But if we were to follow this precedent, we would have to count hundreds of peninsulas that are never given that designation. The term “mainland” would also essentially lose all meaning.


One can, of course, object to these claims by noting that geographical terms are often based on convention rather that strict definition. As the Infoplease article on peninsulas aptly states, “The definition of a peninsula can be a bit arbitrary, and has as much to do with convention and politics as any geographical rules.” I therefore have no problem with casually referring to northwestern Michigan as the “Upper Peninsula,” and I will continue to do so myself. But it is still important to draw attention to geographical conventions that defy geographical definitions.


The prime example of a “geographical convention that defies geographical definitions” is portraying Europe as a continent. As Infoplease further notes, “On a map Europe may look like a peninsula that extends westward from the larger landmass of Eurasia, but historians and geographers have treated it as a separate continent for centuries.” Careful geographers and historians, however, no longer regard Europe as a continent. They insist that it is best regarded, like South Asia, as a subcontinent of Eurasia.