Iowa–South Dakota border

E91942

political boundary state border

The Iowa–South Dakota border is the state line in the north-central United States that largely follows the course of the Big Sioux River, separating Iowa from South Dakota.

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All labels observed (3)

Label	Occurrences
Iowa–South Dakota border canonical	4
South Dakota–Iowa border	3
Iowa–South Dakota state line	1

How this entity was disambiguated

This entity first appeared as the object of triple T776990 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.

NED1 Entity disambiguation (via context triple) gpt-5-mini-2025-08-07

Target entity: Iowa–South Dakota border
Context triple: [Hawarden, Iowa, borderFeature, Iowa–South Dakota border]

A. Siouxland region
The Siouxland region is a tri-state area in the upper Midwest of the United States, centered around Sioux City and encompassing parts of Iowa, Nebraska, and South Dakota.
B. Iowa
Iowa is a Midwestern U.S. state known for its extensive agriculture, especially corn and soybean production, and its role in national politics through the Iowa caucuses.
C. Nebraska–Iowa region
The Nebraska–Iowa region is a bi-state area in the central United States that encompasses communities and economic activity spanning the border between eastern Nebraska and western Iowa, including the Omaha–Council Bluffs metropolitan area.
D. Yankton, South Dakota, United States
Yankton is a small city in southeastern South Dakota known as a historic Missouri River port and the birthplace of NFL kicker Adam Vinatieri.
E. Southwestern Iowa
Southwestern Iowa is a region of the U.S. state of Iowa that encompasses several counties, including Pottawattamie County, and is characterized by its mix of agricultural land, small cities, and proximity to the Missouri River and Omaha metropolitan area.
F. None of above. chosen
G. Unsure - the case is ambiguous/there is not enough information to decide.

NED2 Entity disambiguation (via description) gpt-5-mini-2025-08-07

Target entity: Iowa–South Dakota border
Target entity description: The Iowa–South Dakota border is the state line in the north-central United States that largely follows the course of the Big Sioux River, separating Iowa from South Dakota.

A. Siouxland region
The Siouxland region is a tri-state area in the upper Midwest of the United States, centered around Sioux City and encompassing parts of Iowa, Nebraska, and South Dakota.
B. Iowa
Iowa is a Midwestern U.S. state known for its extensive agriculture, especially corn and soybean production, and its role in national politics through the Iowa caucuses.
C. Nebraska–Iowa region
The Nebraska–Iowa region is a bi-state area in the central United States that encompasses communities and economic activity spanning the border between eastern Nebraska and western Iowa, including the Omaha–Council Bluffs metropolitan area.
D. Yankton, South Dakota, United States
Yankton is a small city in southeastern South Dakota known as a historic Missouri River port and the birthplace of NFL kicker Adam Vinatieri.
E. Southwestern Iowa
Southwestern Iowa is a region of the U.S. state of Iowa that encompasses several counties, including Pottawattamie County, and is characterized by its mix of agricultural land, small cities, and proximity to the Missouri River and Omaha metropolitan area.
F. None of above. chosen

Statements (26)

Predicate	Object
instanceOf	political boundary ⓘ state border ⓘ
country	United States of America ⓘ surface form: United States
crossesNearCity	Sioux City, Iowa ⓘ Sioux Falls, South Dakota ⓘ
definedBy	course of the Big Sioux River ⓘ
establishedInPeriod	19th century ⓘ
follows	Big Sioux River ⓘ
formsPartOf	Iowa–South Dakota border self-linksurface differs ⓘ surface form: Iowa–South Dakota state line
hasAdjacentState	Minnesota ⓘ Nebraska ⓘ
hasDirection	generally north–south ⓘ
hasHydrologicalFeature	Big Sioux River ⓘ
hasLegalStatus	interstate boundary ⓘ
hasNeighboringBorderSegment	Iowa–Minnesota border ⓘ Nebraska–Iowa border ⓘ surface form: Iowa–Nebraska border Minnesota–South Dakota border ⓘ surface form: South Dakota–Minnesota border Nebraska–South Dakota border ⓘ surface form: South Dakota–Nebraska border
locatedInRegion	Midwestern United States ⓘ north-central United States ⓘ
partOf	border of Iowa ⓘ border of South Dakota ⓘ
separates	Iowa ⓘ South Dakota ⓘ
usedFor	administrative division ⓘ jurisdictional division ⓘ

How these facts were elicited

Referenced by (8)

Full triples — surface form annotated when it differs from this entity's canonical label.

Hawarden, Iowa → borderFeature → Iowa–South Dakota border ⓘ

Iowa–South Dakota border → formsPartOf → Iowa–South Dakota border self-linksurface differs ⓘ

this entity surface form: Iowa–South Dakota state line

Sioux City metropolitan area → crossesPoliticalBoundary → Iowa–South Dakota border ⓘ

Nebraska–Iowa border → adjacentTo → Iowa–South Dakota border ⓘ

this entity surface form: South Dakota–Iowa border

Nebraska–South Dakota border → adjacentTo → Iowa–South Dakota border ⓘ

this entity surface form: South Dakota–Iowa border

Rock River → crossesPoliticalBoundary → Iowa–South Dakota border ⓘ

Iowa–Minnesota border → hasNeighboringStateBorder → Iowa–South Dakota border ⓘ

Hudson, South Dakota → borderFeature → Iowa–South Dakota border ⓘ

this entity surface form: South Dakota–Iowa border

All labels observed (3)

How this entity was disambiguated Show

Statements (26)

How these facts were elicited Show

Referenced by (8)

How this entity was disambiguated

How these facts were elicited