# Mad Island

Mad Island is an island in [Lake Superior](https://ontology.bommaritollc.com/id/01a0ddfe-d154-7649-b19b-081f619c450a), [Michigan](https://ontology.bommaritollc.com/id/01a0ca47-57ff-7219-9e2f-cdc1b39bd0fa), in the [Lake Superior (HUC10 0418000002)](https://ontology.bommaritollc.com/id/01a0de92-1f28-711b-9f7e-612909962997) watershed.

IRI: <https://ontology.bommaritollc.com/id/01a0ddfe-bdc9-74df-afe2-38137695e268>

Within: [Michigan](https://ontology.bommaritollc.com/id/01a0ca47-57ff-7219-9e2f-cdc1b39bd0fa) › [Lake Superior](https://ontology.bommaritollc.com/id/01a0ddfe-d154-7649-b19b-081f619c450a)

Type: [geo:Feature](http://www.opengis.net/ont/geosparql#Feature), [schema:Landform](https://schema.org/Landform), [schema:Place](https://schema.org/Place)

Location: 48.12349, -88.50979 (box -88.50979, 48.12349, -88.50979, 48.12349; west, south, east, north)

- `adms:identifier`: [gnis 631306](https://ontology.bommaritollc.com/id/01a0ddfe-bdca-76c5-8fdb-ed5e563c1fec)
- `dcterms:type`: [island](https://ontology.bommaritollc.com/vocab/geo/gnisIsland)
- `geo:hasDefaultGeometry`: [point of Mad Island](https://ontology.bommaritollc.com/id/01a0ddfe-f540-7677-a194-7b0b568164d9)
- `geo:hasGeometry`: [point of Mad Island](https://ontology.bommaritollc.com/id/01a0ddfe-f540-7677-a194-7b0b568164d9)
- **in watershed** (`bcgeo:inWatershed`): [Lake Superior (HUC10 0418000002)](https://ontology.bommaritollc.com/id/01a0de92-1f28-711b-9f7e-612909962997)
- `prov:wasDerivedFrom`:
  - [evidence from https://prd-tnm.s3.amazonaws.com/StagedProducts/GeographicNames/DomesticNames/DomesticNames\_MI\_Text.zip](https://ontology.bommaritollc.com/id/01a0ddfe-bdc9-74df-afe2-381221038cf4)
  - [evidence from https://3dhp.nationalmap.gov/arcgis/rest/services/usgs\_3dhp\_all/FeatureServer](https://ontology.bommaritollc.com/id/01a0de32-5396-716b-afc5-3888c8a41e4d)
  - [evidence from https://3dhp.nationalmap.gov/arcgis/rest/services/usgs\_3dhp\_all/FeatureServer](https://ontology.bommaritollc.com/id/01a0de86-db90-7246-aba9-06427170896e)
  - [evidence from https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer](https://ontology.bommaritollc.com/id/01a0de92-1939-71b3-adca-17a7cd9aeac4)
- `schema:containedInPlace`:
  - [Keweenaw County](https://ontology.bommaritollc.com/id/01a0ca47-5d2f-7501-b2ba-1fe0d1e4fc6a)
  - [Houghton Township](https://ontology.bommaritollc.com/id/01a0ca47-7cd1-7618-8ec3-65ca0f1f1532)
  - [Lake Superior](https://ontology.bommaritollc.com/id/01a0ddfe-d154-7649-b19b-081f619c450a)
- `skos:prefLabel`: Mad Island

## Elsewhere

- [Wikidata Q49655835](https://www.wikidata.org/wiki/Q49655835) (proposed match (exactMatch))
- [USGS GNIS 631306](https://edits.nationalmap.gov/apps/gaz-domestic/public/summary/631306) (gnis)
- [OpenStreetMap](https://www.openstreetmap.org/?mlat=48.12349&mlon=-88.50979#map=14/48.12349/-88.50979) (48.12349, -88.50979)
- [Google Maps](https://www.google.com/maps/search/?api=1&query=48.12349,-88.50979)
- [Source](https://prd-tnm.s3.amazonaws.com/StagedProducts/GeographicNames/DomesticNames/DomesticNames_MI_Text.zip) (prd-tnm.s3.amazonaws.com)
- [Source](https://3dhp.nationalmap.gov/arcgis/rest/services/usgs_3dhp_all/FeatureServer) (3dhp.nationalmap.gov)
- [Source](https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer) (hydro.nationalmap.gov)

## Pointing here

- Mappings (1; `owl:annotatedSource`):
  - [exactMatch http://www.wikidata.org/entity/Q49655835 (proposed)](https://ontology.bommaritollc.com/id/01a0ddff-75f8-775d-9df1-f65a1a3320b8)

---
Also as: [Turtle](https://ontology.bommaritollc.com/id/01a0ddfe-bdc9-74df-afe2-38137695e268.ttl), [JSON-LD](https://ontology.bommaritollc.com/id/01a0ddfe-bdc9-74df-afe2-38137695e268.jsonld), [N-Triples](https://ontology.bommaritollc.com/id/01a0ddfe-bdc9-74df-afe2-38137695e268.nt), [HTML](https://ontology.bommaritollc.com/id/01a0ddfe-bdc9-74df-afe2-38137695e268)
Cite as: Mad Island. bc-ontology, release 0.1.0-rc12, 2026-09-27. https://ontology.bommaritollc.com/id/01a0ddfe-bdc9-74df-afe2-38137695e268
Release 0.1.0-rc12, graph hash a20f66b983549f220c6f061b7e40233771a06aa47a0c0aede95a2a57ee2e9553.