Mason–Dixon Line
E21202
The Mason–Dixon Line is the historic boundary surveyed in the 18th century between several American colonies that later came to symbolize the cultural and political divide between the Northern and Southern United States.
All labels observed (5)
| Label | Occurrences |
|---|---|
| Mason–Dixon line | 5 |
| Mason–Dixon Line canonical | 2 |
| Mason and Dixon line | 1 |
| Mason–Dixon Line later associated with cultural boundary between U.S. North and South | 1 |
| Mason–Dixon Line survey | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T170153 — 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: Mason–Dixon Line Context triple: [Gettysburg, Pennsylvania, near, Mason–Dixon Line]
-
A.
Manassas Line
The Manassas Line is a commuter rail route in Northern Virginia that connects suburban communities to Washington, D.C. as part of the Virginia Railway Express system.
-
B.
Fredericksburg Line
The Fredericksburg Line is a Virginia Railway Express commuter rail route that connects Washington, D.C. with communities in Northern Virginia along the I-95 corridor.
-
C.
Shenandoah Valley
The Shenandoah Valley is a fertile and historic region of western Virginia and eastern West Virginia, nestled between the Blue Ridge and Allegheny Mountains and renowned for its scenic landscapes, agriculture, and Civil War heritage.
-
D.
Broad Run, Virginia
Broad Run, Virginia is an unincorporated community in Prince William County best known as the western terminus of the Virginia Railway Express Manassas Line and its associated commuter rail station and yard.
-
E.
Powell–Mason line
The Powell–Mason line is one of San Francisco’s historic cable car routes, running between downtown and the Fisherman’s Wharf area and serving as both public transit and a popular tourist attraction.
- 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: Mason–Dixon Line Target entity description: The Mason–Dixon Line is the historic boundary surveyed in the 18th century between several American colonies that later came to symbolize the cultural and political divide between the Northern and Southern United States.
-
A.
Manassas Line
The Manassas Line is a commuter rail route in Northern Virginia that connects suburban communities to Washington, D.C. as part of the Virginia Railway Express system.
-
B.
Fredericksburg Line
The Fredericksburg Line is a Virginia Railway Express commuter rail route that connects Washington, D.C. with communities in Northern Virginia along the I-95 corridor.
-
C.
Shenandoah Valley
The Shenandoah Valley is a fertile and historic region of western Virginia and eastern West Virginia, nestled between the Blue Ridge and Allegheny Mountains and renowned for its scenic landscapes, agriculture, and Civil War heritage.
-
D.
Broad Run, Virginia
Broad Run, Virginia is an unincorporated community in Prince William County best known as the western terminus of the Virginia Railway Express Manassas Line and its associated commuter rail station and yard.
-
E.
Powell–Mason line
The Powell–Mason line is one of San Francisco’s historic cable car routes, running between downtown and the Fisherman’s Wharf area and serving as both public transit and a popular tourist attraction.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
historical boundary
ⓘ
surveyed border line ⓘ |
| alsoKnownAs |
Mason–Dixon Line
ⓘ
surface form:
Mason and Dixon line
|
| approximateLength | about 233 miles ⓘ |
| associatedWith |
American Civil War era regional divisions
ⓘ
slavery in the United States ⓘ |
| completedIn | 1767 ⓘ |
| coordinateSystemUsed | celestial observations ⓘ |
| country |
United States of America
ⓘ
surface form:
United States
|
| definedBy | agreement between the Penn family and the Calvert family ⓘ |
| endPoint | near the crest of the Appalachian Mountains ⓘ |
| followsParallel | 39th parallel north (approximate) ⓘ |
| hasHeritageStatus | listed on the U.S. National Register of Historic Places (in parts) ⓘ |
| historicalEra | 18th century ⓘ |
| influenced | later U.S. state boundary definitions ⓘ |
| legalStatus | colonial boundary line ⓘ |
| locatedIn | Eastern United States ⓘ |
| markedBy |
crownstones with family coats of arms
ⓘ
stone markers ⓘ |
| namedAfter |
Charles Mason
ⓘ
Charles Mason ⓘ
surface form:
Jeremiah Dixon
|
| partOf |
borders of Delaware
ⓘ
borders of Maryland ⓘ borders of Pennsylvania ⓘ borders of West Virginia ⓘ |
| precededBy | earlier, disputed colonial boundary claims ⓘ |
| purpose | to resolve a border dispute between Pennsylvania and Maryland ⓘ |
| region |
Mid-Atlantic states
ⓘ
surface form:
Mid-Atlantic United States
|
| separates |
Province of Delaware
ⓘ
surface form:
Delaware
Maryland ⓘ Maryland and Delaware ⓘ Maryland and Pennsylvania ⓘ Maryland and West Virginia ⓘ Pennsylvania ⓘ West Virginia ⓘ |
| startPoint | near the Delaware River ⓘ |
| surveyedFor |
British Crown colonies in North America
ⓘ
Colony of Maryland ⓘ
surface form:
Province of Maryland
Province of Pennsylvania ⓘ |
| surveyEndYear | 1767 ⓘ |
| surveyMethod |
astronomical surveying
ⓘ
chain measurement ⓘ |
| surveyor |
Charles Mason
ⓘ
Charles Mason ⓘ
surface form:
Jeremiah Dixon
|
| surveyStartYear | 1763 ⓘ |
| symbolizes |
boundary between Northern United States and Southern United States
ⓘ
cultural divide in the United States ⓘ political divide in the United States ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Mason–Dixon Line Description of subject: The Mason–Dixon Line is the historic boundary surveyed in the 18th century between several American colonies that later came to symbolize the cultural and political divide between the Northern and Southern United States.
Referenced by (10)
Full triples — surface form annotated when it differs from this entity's canonical label.
subject surface form:
Gettysburg, Pennsylvania
this entity surface form:
Mason and Dixon line
this entity surface form:
Mason–Dixon line
this entity surface form:
Mason–Dixon line
subject surface form:
Blue Ridge Summit, Pennsylvania
this entity surface form:
Mason–Dixon line
this entity surface form:
Mason–Dixon Line survey
this entity surface form:
Mason–Dixon Line later associated with cultural boundary between U.S. North and South
this entity surface form:
Mason–Dixon line
this entity surface form:
Mason–Dixon line