Present-day Keg Island exists in the Mississippi River where the river flows between the states of Iowa and Illinois. It is over a mile long, maybe a quarter of a mile wide at its widest point, consisting of about 128 acres – and it is uninhabited. Burlington Basket Company claims title to the island by virtue of an Illinois chain of title dating back to an 1899 quit-claim deed out of the state. The Iowa Department of Natural Resources (DNR) believes that it owns the island because the navigable channel of the Mississippi River flows on the Illinois side, meaning that it is currently within the borders of Iowa. The battle over the ownership went to trial in Iowa District Court where a decision was made in Burlington’s favor. The DNR appealed to the Iowa Supreme Court, which handed down its decision in State v. Burlington Basket Co.1

Figure 1 is a composite drawing showing a modern-day Topo Quad-Map of the Mississippi River, Keg Island (near the bend in the river), and two other islands: Otter Island and Turkey Island. The river flows from north to south in this picture, and the navigable channel and state boundary line are depicted east of Keg Island.

survey map of Keg Island in Mississippi River

Overlaying this map is the survey of the river by the General Land Office (GLO) in 18422 (in blue) from the Iowa side of the river, and the 1844 GLO survey3 (in red) conducted on the Illinois side. Significant to the discussion is that the 1842 survey located two islands in the Mississippi River and depicts the east bank. In contrast, the 1844 survey only went to the east bank and did not depict any islands in the river. Conspicuously missing from both surveys is anything resembling Keg Island. 

In the 1980’s and mid 1990’s, DNR posted signs on the island relative to public use and hunting on the sovereign islands of the State of Iowa. In 1994 or 1995, DNR employees noticed evidence of some logging activity and, upon further investigation, discovered Burlington’s claim to the island through its Illinois title. Although Burlington did not occupy the island, it occasionally harvested timber to be used in its basket making operations. The State brought suit against Burlington to quite title in the state because of its right to the ownership of islands on the Iowa side of the Iowa-Illinois boundary in the Mississippi River and to enjoin Burlington from removing any more timber.


River Boundary Law

At this point, the court entered into a very instructive refresher-course on basic river boundary law, including the “island rule.” Quoting the United States Supreme Court4 and other Iowa cases, the Court explained:

When a navigable river constitutes the boundary between two independent states, the line defining the point at which the jurisdiction of the two separates is well established to be the middle of the main channel of the stream. The interest of each state in the navigation of the river admits of no other line. The preservation by each of its equal rights in the navigation of the stream is the subject of paramount interest. Where several channels exist, the main channel of the river is the middle of the principal one, or, rather, the one usually followed by boats. The principal navigable channel is not necessarily where the water is the deepest. Vessels do not follow a narrow, crooked channel, close to shore, however deep, when they can proceed on a safer and more direct one with sufficient water.”5

This is what is generally referred to as the “thalweg rule.” The thalweg, being the deepest channel, will generally be the navigable channel, but not always.

The court went on to explain that in Iowa, the sovereign owns the submerged lands in the Mississippi River and the upland owner owns to the highwater mark. This is the most typical scenario in the public land states, because the federal government only claimed the land down to the highwater mark, reserving the submerged lands under navigable waters for the future states. This meant that the federal government would only convey land down to the highwater mark and not beyond. However, this is not necessarily a universal rule even in public domain states, because Illinois, for example, recognizes that the upland owner owns the submerged lands under the Mississippi River, even though it is probably well documented that the Mississippi River is navigable-in-fact for title purposes. If a state wants to divest itself of its submerged lands, it may do so, but the federal government could not.

Other rules were explained including movement of the river and the state boundary through accretions and even boat traffic. If the navigable channel moves within the river, then the state boundaries move with the boat traffic. If you want to know where the state boundary is located in a navigable river, watch the boat traffic. It is not necessarily the deepest channel. Avulsive events were also discussed and how they generally do not move boundaries, including state boundaries. Another important point to be made relative to the movement of a river is that the presumption will always be that the movement occurred through accretions and not by an avulsive event. The court explained the difference between a presumption, which is a presumed state of affairs that is rebuttable, and an inference which “is merely some evidence from which a fact finder may infer”6 a certain state of affairs. “In a sense, therefore, a presumption is an inference which is mandatory unless rebutted.”7


The Island Rule

Finally, the court came to the “island rule” or what is sometimes referred to the “island exception to the thalweg rule.” If an island forms in a river, then it belongs to the owner of the submerged lands from which it arose. On the Iowa side of the boundary, that would be the state, and on the Illinois side, that would be the upland owner. With an island in the middle of a navigable river between two states, the respective dates of statehood also become important. Illinois entered statehood in 1818 and Iowa followed in 1846. If Keg Island was in existence in 1818 or otherwise formed in the river prior to 1846 on the Illinois side of the navigable channel, it would always and forever be within the boundaries of the State of Illinois, no matter where the thalweg might move to. If Illinois could not claim the island during this time period (the navigable channel never moving west of Keg Island), then when Iowa became a state in 1846, the island would forever be within the borders of Iowa.

The state claimed that Burlington had the burden to prove that Keg Island existed in 1818 or formed east of the thalweg prior to Iowa becoming a state.

The State’s arguments are contrary to the well-established principle that the plaintiff in a quiet title action must succeed on the strength of its own title and not on the weakness of the defendant’s title. Therefore, the focus must be on whether the State proved that it had sovereign title to the island, not whether BBC had a valid record title. The absence of the latter is not proof of the former.”8

So, it was the state’s burden to prove the contrary, which it ultimately was unable to do.

The state also argued that since the navigable channel is currently on the Illinois side of Keg Island, that it is entitled to a presumption that it always has been. The court noted that the proper classification of the relationship between a present existence and a prior or subsequent existence is an inference and not a presumption. Not only did the state not get the presumption, the evidence at trial demonstrated that the river had been channelized since at least some time in the 1870's.


What About Keg Island?

So, when and where did Keg Island come from?

The witnesses offered varying explanations for the absence of Keg Island from the Whitcher survey [the 1842 GLO survey, conducted from the Iowa side of the river]: (1) Keg Island did not exist in 1842; (2) if it did exist, it was located on the Illinois side of the thalweg; or (3) if it did exist and if it was located on the Iowa side of the thalweg, it was not significant enough to be included in the survey.

Conspicuously absent from the discussion was the fact that the 1842 GLO plat shows the entire river, from bank to bank. Why would Whitcher leave out an existing island between the two banks he presumably surveyed? Also absent was any discussion of the 1844 GLO survey, which doesn’t show any islands in the river. The winning argument9 seems to have been “that Keg Island or its predecessors did in fact exist at the time of the Whitcher survey but because they were located on the Illinois side of the main navigational channel, they were not within the Iowa territory surveyed by Whitcher.” If this argument is true, somebody from the state’s side should have produced the 1844 GLO plat.

The winning argument would also support the idea that the federal government still owns Keg Island, if it never conveyed it. The only way that I could see Illinois being able to convey Keg Island is if it formed out of the submerged lands belonging to the state between 1818 and 1846, and prior to any conveyance of the upland to private property owners who would then own the submerged lands from which Keg Island arose. These are interesting points to ponder, but in all likelihood, this will remain the unsolved mystery of Keg Island.


  1. State of Iowa v. Burlington Basket Company, 651 N.W.2d 29 (Iowa 2002).
  2. Referred to in the opinion as the “1842 survey conducted by J.E. Whitcher.”
  3. The 1844 GLO survey is not referred to at all in the opinion and presumably was not entered into evidence.
  4. The Supreme Court of the United States (SCOTUS) is a court of limited jurisdiction and generally does not have jurisdiction over private property rights. However, it does have jurisdiction over state boundaries and as a consequence does, to a limited degree, have authority over water boundary law, rendering some aspects of water boundary law universal in all states. 
  5. State v. Burlington, at 31-32 (internal punctuation and citations omitted).
  6. Id. at 36.
  7. Id.
  8. Id. at 34 (internal punctuation and citations omitted).
  9. In addition to the fact that the state did not carry its burden of proof.

Neither the author nor POB intend this column to be a source of legal advice for surveyors or their clients. The law changes and differs in important respects for different jurisdictions. If you have a specific legal problem, the best source of advice is an attorney admitted to the bar in your jurisdiction.