Apologies if this is a poorly written question, I'm writing this on my phone.

I noticed that there were a lot of rather long rivers in the region in question, and I began to wonder just how connected they are. I came up with the following path:

Start in Mobile, Alabama, and head north along the Tombigbee River past the Mississippi-Alabama border and into Mississippi. It seems to go through some name changes, but near the Tennessee-Alabama-Mississippi border, it connects with the Tennessee River. Follow the Tennessee River north through Kentucky and Kentucky Lake, where it will eventually meet the Ohio River. That, in turn, feeds into the Mississippi River, which flows back to the Gulf of Mexico.

It seems to me that it makes the region enclosed an island, since it is impossible to reach it without crossing a body of water. But is this significant in any other way? I can tell that not all the rivers flow in the same direction, and it's possible that some portions of the water around it were artificially created, is there anything else that comes as a result of this?

  • $\begingroup$ i do not think the land area fills the criteria of beeing an island even with the rivers and lakes en.wikipedia.org/wiki/Island $\endgroup$ Jun 16, 2020 at 15:06
  • $\begingroup$ Yeah, a matter of argumentation. "Islands" come and go with rise and fall of the watertable, construction work and politics. If you like it to be an island, go ahead. Others might not understand the argumentation, i'd argue that an island needs to be girdled round by a common watertable, not a chain of canals and rivers. $\endgroup$
    – user20217
    Jun 17, 2020 at 11:42
  • $\begingroup$ How is this question not about Earth Science? Voting to reopen. $\endgroup$ Jun 17, 2020 at 12:54
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    $\begingroup$ Some other examples are Isa Lake in Wyoming, which drains to the Pacific and the Gulf of Mexico; Wollaston Lake in Saskatchewan, which drains to the Mackenzie and Churchill rivers; Divide Creek on the Alberta / British Columbia border, which forks at the continental divide to drain to both the Pacific Ocean and Hudson Bay; and several lakes in Finland. There are other manmade and natural weird drainage systems in the world. $\endgroup$ Jun 17, 2020 at 13:08
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    $\begingroup$ @a_donda - I discussed the Committee's Punch Bowl in my answer. It's a tiny natural lake that sits directly on the continental divide in Canada's Jasper National Park. The lake's drains to both the Pacific and the Arctic. Is there any distinction between natural waterways and manmade ones regarding what constitutes an island? $\endgroup$ Jun 17, 2020 at 23:14

2 Answers 2


Rhetorical questions:

  • Does the Erie Canal, which connects the Hudson River with Lake Erie make northern New York, southern Quebec, all of New England, all of New Brunswick, and the non-island parts of Nova Scotia an island?

  • Does the Chicago Sanitary and Ship Canal make all of the eastern part of the US an island?

  • Does Russia's Unified Deep Water System make Finland, Scandinavia, and Estonia an island, and mainland Europe another island?

Humankind has learned to connect waterways with canals, locks, and dams. The sudden appearance of those canals, locks, and dams does not suddenly make those now disconnected lands into islands. The connection between the Tombigbee and the Tennessee rivers involves manmade canyons, manmade canals, and several manmade locks and dams.

What about naturally narrow waterway connections? As an extreme example, consider the Committee's Punch Bowl in Alberta, Canada. This little lake has two little outlets. One of the outlets eventually joins the MacKenzie River, which flows into the Arctic Ocean. The other eventually joins the Columbia River, which flows into the Pacific Ocean.

This leads to one last rhetorical question: Does the natural existence of the Committee's Punch Bowl make most of Washington state, most of British Columbia, almost all of the Yukon, and all of mainland Alaska into a very large "island"? Most geographers would say no.


It is possible to travel up the Tombigbee River to the Tennessee River. This is because parts of the Tombigbee River are man made.


The key part seems to be the "Divide Cut," a canal linking the Tennessee and Tombigbee Rivers.

  • $\begingroup$ you do not answer the question is it an island. $\endgroup$ Jun 16, 2020 at 18:30

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