Halfway Rock Light
E168957
Halfway Rock Light is an offshore lighthouse in Maine that marks a hazardous ledge in Casco Bay and aids navigation for vessels entering Portland Harbor.
All labels observed (2)
| Label | Occurrences |
|---|---|
| Halfway Rock Light canonical | 3 |
| Halfway Rock ledge | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T1478551 — 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: Halfway Rock Light Context triple: [Casco Bay, hasLighthouse, Halfway Rock Light]
-
A.
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.
-
B.
Tahkuna Lighthouse
Tahkuna Lighthouse is a historic cast-iron lighthouse located on the northern tip of Hiiumaa Island in Estonia, known for being one of the tallest lighthouses in the country.
-
C.
Big Red Lighthouse
Big Red Lighthouse is a historic, bright-red navigational beacon at the channel entrance to Lake Michigan in Holland, Michigan, and a well-known local icon.
-
D.
Boca Chita Lighthouse
Boca Chita Lighthouse is a small, historic ornamental lighthouse located on Boca Chita Key in Biscayne National Park, Florida, known as a picturesque landmark rather than an active navigational aid.
-
E.
Umpqua River Lighthouse
Umpqua River Lighthouse is a historic coastal beacon in Oregon known for its distinctive red-and-white flashing Fresnel lens and scenic views over the Pacific Ocean.
- 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: Halfway Rock Light Target entity description: Halfway Rock Light is an offshore lighthouse in Maine that marks a hazardous ledge in Casco Bay and aids navigation for vessels entering Portland Harbor.
-
A.
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.
-
B.
Tahkuna Lighthouse
Tahkuna Lighthouse is a historic cast-iron lighthouse located on the northern tip of Hiiumaa Island in Estonia, known for being one of the tallest lighthouses in the country.
-
C.
Big Red Lighthouse
Big Red Lighthouse is a historic, bright-red navigational beacon at the channel entrance to Lake Michigan in Holland, Michigan, and a well-known local icon.
-
D.
Boca Chita Lighthouse
Boca Chita Lighthouse is a small, historic ornamental lighthouse located on Boca Chita Key in Biscayne National Park, Florida, known as a picturesque landmark rather than an active navigational aid.
-
E.
Umpqua River Lighthouse
Umpqua River Lighthouse is a historic coastal beacon in Oregon known for its distinctive red-and-white flashing Fresnel lens and scenic views over the Pacific Ocean.
- F. None of above. chosen
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
lighthouse
ⓘ
offshore lighthouse ⓘ |
| access | only by boat ⓘ |
| addedToNRHP | 1988 ⓘ |
| ARLHSNumber | ARLHS USA-364 ⓘ |
| associatedHarbor | Portland Harbor ⓘ |
| automated | yes ⓘ |
| automationYear | 1975 ⓘ |
| climateExposure | fully exposed to open sea conditions ⓘ |
| constructionMaterial | granite ⓘ |
| country |
United States
ⓘ
linked to:
United States of America
|
| currentLens | modern optic ⓘ |
| distanceFromShore | approximately 10 miles offshore ⓘ |
| focalHeight | 76 feet ⓘ |
| fogSignal | horn ⓘ |
| foundation | rock ⓘ |
| hasStructure |
boat landing
ⓘ
keeper’s quarters ⓘ |
| hazardType | submerged ledges ⓘ |
| height | 76 feet ⓘ |
| heritageStatus | listed on the National Register of Historic Places ⓘ |
| historicUse | aids to navigation station ⓘ |
| lightCharacteristic | white flash every 15 seconds ⓘ |
| locatedIn |
Casco Bay
ⓘ
Gulf of Maine ⓘ Maine ⓘ Portland, Maine metropolitan area ⓘ
linked to:
Greater Portland, Maine
|
| locatedOff | Harpswell, Maine ⓘ |
| managedBy | United States Coast Guard ⓘ |
| marking | unpainted granite tower ⓘ |
| marks |
Halfway Rock ledge
ⓘ
linked to:
Halfway Rock Light
|
| navigationalNumber | USCG Light List number 1-0045 ⓘ |
| NRHPType | historic district contributing property ⓘ |
| originalLens |
second-order Fresnel lens
ⓘ
linked to:
Fresnel lens
|
| originallyBuiltBy | United States Lighthouse Board ⓘ |
| owner | private owner ⓘ |
| powerSource | solar power ⓘ |
| previousOwner | United States Coast Guard ⓘ |
| purpose |
aids navigation
ⓘ
marks hazardous ledge ⓘ |
| region | New England ⓘ |
| serves | vessels entering Portland Harbor ⓘ |
| soldAtAuction | 2014 ⓘ |
| towerShape | conical tower ⓘ |
| USCGDistrict | First Coast Guard District ⓘ |
| waterBody | Atlantic Ocean ⓘ |
| yearLit | 1871 ⓘ |
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: Halfway Rock Light Description of subject: Halfway Rock Light is an offshore lighthouse in Maine that marks a hazardous ledge in Casco Bay and aids navigation for vessels entering Portland Harbor.
Referenced by (4)
Full triples — surface form annotated when it differs from this entity's canonical label.
linked to: Halfway Rock Light