Spring Point Ledge Light
E174059
Spring Point Ledge Light is a historic caisson-style lighthouse off South Portland, Maine, that marks a dangerous ledge in Casco Bay and guides vessels entering Portland Harbor.
All labels observed (2)
| Label | Occurrences |
|---|---|
| Spring Point Ledge Light canonical | 3 |
| Spring Point Ledge Light Trust | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T1478548 — 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: Spring Point Ledge Light Context triple: [Casco Bay, hasLighthouse, Spring Point Ledge Light]
-
A.
Brant Point Light
Brant Point Light is a historic lighthouse on Nantucket Island, Massachusetts, guiding vessels into Nantucket Harbor and known as one of the oldest lighthouse sites in the United States.
-
B.
Eastern Point Lighthouse
Eastern Point Lighthouse is a historic coastal beacon in Gloucester, Massachusetts, guiding ships at the entrance to Gloucester Harbor on the Atlantic Ocean.
-
C.
Nauset Light
Nauset Light is a historic, red-and-white lighthouse on Cape Cod in Massachusetts, known as an iconic coastal landmark and symbol of the region.
-
D.
Great Point Light
Great Point Light is a historic lighthouse located at the northern tip of Nantucket Island, Massachusetts, guiding vessels through the surrounding coastal waters.
-
E.
Long Point Light
Long Point Light is a historic lighthouse marking the entrance to Provincetown Harbor at the tip of Cape Cod, Massachusetts.
- 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: Spring Point Ledge Light Target entity description: Spring Point Ledge Light is a historic caisson-style lighthouse off South Portland, Maine, that marks a dangerous ledge in Casco Bay and guides vessels entering Portland Harbor.
-
A.
Brant Point Light
Brant Point Light is a historic lighthouse on Nantucket Island, Massachusetts, guiding vessels into Nantucket Harbor and known as one of the oldest lighthouse sites in the United States.
-
B.
Eastern Point Lighthouse
Eastern Point Lighthouse is a historic coastal beacon in Gloucester, Massachusetts, guiding ships at the entrance to Gloucester Harbor on the Atlantic Ocean.
-
C.
Nauset Light
Nauset Light is a historic, red-and-white lighthouse on Cape Cod in Massachusetts, known as an iconic coastal landmark and symbol of the region.
-
D.
Great Point Light
Great Point Light is a historic lighthouse located at the northern tip of Nantucket Island, Massachusetts, guiding vessels through the surrounding coastal waters.
-
E.
Long Point Light
Long Point Light is a historic lighthouse marking the entrance to Provincetown Harbor at the tip of Cape Cod, Massachusetts.
- F. None of above. chosen
Statements (46)
| Predicate | Object |
|---|---|
| instanceOf |
caisson lighthouse
ⓘ
lighthouse ⓘ |
| accessType | pedestrian access via breakwater ⓘ |
| automated | 1960 ⓘ |
| category |
Buildings and structures in South Portland, Maine
ⓘ
Lighthouses in Maine ⓘ Transportation in Cumberland County, Maine ⓘ |
| connectedToShoreBy | granite breakwater ⓘ |
| constructionMaterial |
brick
ⓘ
cast iron ⓘ |
| constructionStartDate | 1896 ⓘ |
| coordinates | 43.647°N 70.225°W ⓘ |
| country |
United States of America
ⓘ
surface form:
United States
|
| county | Cumberland County, Maine ⓘ |
| firstLit | 1897 ⓘ |
| focalHeight | 54 feet ⓘ |
| fogSignal | horn ⓘ |
| foundation | caisson ⓘ |
| function | aids to navigation ⓘ |
| hasAccess | breakwater walkway ⓘ |
| hasTour | guided tours in season ⓘ |
| height | 54 feet ⓘ |
| heritageStatus | historic structure ⓘ |
| inception | 1897 ⓘ |
| lightCharacteristic | Flashing white every 6 seconds ⓘ |
| listedOn | National Register of Historic Places ⓘ |
| locatedInBodyOfWater | Casco Bay ⓘ |
| locatedInWaterArea | Portland Harbor ⓘ |
| locatedOn | Spring Point Ledge ⓘ |
| location | South Portland, Maine ⓘ |
| managingOrganization |
Spring Point Ledge Light
self-linksurface differs
ⓘ
surface form:
Spring Point Ledge Light Trust
|
| marking | white tower with black lantern and trim ⓘ |
| nearbyCity | Portland, Maine ⓘ |
| nearbyLandmark | Southern Maine Community College ⓘ |
| NRHPListingYear | 1988 ⓘ |
| NRHPType | historic lighthouse ⓘ |
| openToPublic | yes ⓘ |
| originalLensType |
Fresnel lens
ⓘ
surface form:
Fourth-order Fresnel lens
|
| owner | United States Coast Guard ⓘ |
| powerSource | electric ⓘ |
| purpose |
to guide vessels entering Portland Harbor
ⓘ
to mark Spring Point Ledge ⓘ |
| region | New England ⓘ |
| state | Maine ⓘ |
| towerShape | cylindrical tower with balcony and lantern ⓘ |
| waterway | Atlantic Ocean ⓘ |
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: Spring Point Ledge Light Description of subject: Spring Point Ledge Light is a historic caisson-style lighthouse off South Portland, Maine, that marks a dangerous ledge in Casco Bay and guides vessels entering Portland Harbor.
Referenced by (4)
Full triples — surface form annotated when it differs from this entity's canonical label.
Spring Point Ledge Light
→
managingOrganization
→
Spring Point Ledge Light
self-linksurface differs
ⓘ
this entity surface form:
Spring Point Ledge Light Trust
subject surface form:
Portland Harbor