# Illinois v. Kentucky

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United States Supreme Court
500 U.S. 380
Illinois v. Kentucky
No. 106, Orig Argued: March 18, 1991. --- Decided: May 28, 1991
Syllabus
In a dispute between Illinois and Kentucky over their common boundary, the Special Master has recommended that this Court determine the boundary to be the "low-water mark on the northerly side of the Ohio River as it existed in the year 1792," rather than the river's northerly low-water mark "as it exists from time to time"; find that the record does not support Kentucky's affirmative defenses of acquiescence and laches and its defenses based on "principles of riparian boundaries, including accretion, erosion and avulsion"; find that the construction of dams on the river has caused the present low-water mark on the Illinois side to be farther north than it was in 1792; and order the two States' common boundary to be determined as nearly as the 1792 line can now be ascertained. Kentucky has filed exceptions.
Held:
1. The boundary is the line of the low-water mark as it was in 1792. Pp. 383-388.
(a) This is the rule that was used to determine the boundary between Kentucky and its neighboring States of Ohio, Ohio v. Kentucky, 444 U.S. 335, 100 S.Ct. 588, 62 L.Ed.2d 530, and Indiana, Indiana v. Kentucky, 136 U.S. 479, 10 S.Ct. 1051, 34 L.Ed. 329; and the history and precedent that supplied the rule in those cases govern here. Pp. 383-384.
(b) Kentucky has not proved that, under the doctrine of prescription and acquiescence, the boundary is a transient low-water mark. The record fails to support Kentucky's claim of a long and continuous possession of, and assertion of sovereignty over, land within the territory delimited by the transient mark. Kentucky has imposed property taxes on only 3 of the 15 structures extending into the territory in question. And evidence of its ad valorem taxation of barges and other watercraft traveling on the river fails to speak directly to the boundary issue, since it is undisputed that the sailing line on the river is within Kentucky's boundary and jurisdiction, and since barges and watercraft would rarely venture near the disputed territory. Moreover, both the Legislative Research Commission of the Kentucky General Assembly and the Commonwealth's Attorney General have made references to the 1792 low-water mark as the boundary. Nor does the record support the claim of Illinois' acquiescence. The descriptions of the boundary as following "along [the Ohio River's] north-western shore" in earlier versions of the Illinois Constitution are verbatim recitations of the congressional language describing Illinois' boundary in that State's Enabling Act, and the Special Master correctly reasoned that Congress intended Illinois' southern boundary to be the same as that granted Ohio and Indiana when they were formed. In addition, the Illinois Supreme Court took an even less hospitable view toward Kentucky's claim than the State Constitution when it adopted, and used for almost 50 years, a theory that would have ratchetted the boundary line forever southward toward the river's deepest point. Pp. 384-388.
(c) Kentucky's other affirmative defenses are likewise unavailing. The laches defense is generally inapplicable against a State. And the defenses based on the "principles of riparian boundaries" require no extended consideration, for Kentucky concedes that these would affect the ultimate boundary determination only if it prevailed on the issues of prescription and acquiescence. Pp. 388-389.
2. Kentucky's exception to the recommended finding that the construction of dams on the river has permanently raised its level above that of 1792, consequently placing the present low-water mark on the Illinois side farther north than it was in 1792, is sustained. Any question about the relative locations of the 1792 line and today's low-water mark is premature and should be determined after the Special Master has made further recommendations to resolve any disputes the parties may have about the exact location of the 1792 line. P. 389.
Exceptions to Special Master's Report sustained in part and overruled in part, Report adopted in part, and case remanded.
SOUTER, J., delivered the opinion for a unanimous Court.
Rickie Leon Pearson, Frankfort, Ky., for defendant.
John Brunsman, Springfield, Ill., for plaintiff.
Justice SOUTER delivered the opinion of the Court.

## Notes

This work is in the public domain in the United States because it is a work of the United States federal government (see 17 U.S.C. 105).
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