Satellite Imagery
Satellite Imagery
HER: Archaeological Survey of Ireland SMR Database MA005-003 (None)
NMR: MA 005 (None)
SM: None
NGR: None
X: 498313 Y: 842573 (IRENET95)
This possible coastal promontory fort, marked as 'Horse Island' on the first edition OS six-inch map, is situated N of Belderg Harbour and c. 2.9km from the town. The triangular penninsula which projects to the NE can no longer be accessed from the mainland as any bridge to the mainland on the SW has been eroded out in a deep cleft 20m wide. The island has an overall foortprint of c. 4.78ha and rises into a rocky dome. Westropp records the remains of a wall comprising 'at the head of the slope, foundation blocks, in line, and in places, a few courses high' (1912, 120). He observed that the wall was 'ready to slide down if the shaken bank gives way below'. Unfortunately, no other information is available as to the composition of this wall or any other internal features on the landmass.
Citizen Science: ✗
Reliability of Data: Unconfirmed
Reliability of Interpretation: Unconfirmed
X: -1064559 Y: 7231327 (EPSG: 3857)
Longitude: -9.563097914065615 Latitude: 54.32174195011611 (EPSG:4326)
Country: Republic of Ireland
Current County or Unitary Authority: Mayo
Historic County: Mayo
Current Parish/Community/Council/Townland: Horse Island
None
| Extant | ✗ |
| Cropmark | ✗ |
| Likely Destroyed | ✓ |
None
| Woodland | ✗ |
| Commercial Forestry Plantation | ✗ |
| Parkland | ✗ |
| Pasture (Grazing) | ✓ |
| Arable | ✗ |
| Scrub/Bracken | ✗ |
| Bare Outcrop | ✗ |
| Heather/Moorland | ✗ |
| Heath | ✗ |
| Built-up | ✗ |
| Coastal Grassland | ✗ |
| Other | ✗ |
The triangular penninsula which projects to the NE can no longer be accessed from the mainland as two long creeks have cut through any neck to form a continuous cleft 20m wide on the SW side. The island has an overall foortprint of c. 4.78ha and rises into a rocky dome. Westropp records the remains of a wall 'at the head of the slope'.
| Contour Fort | ✗ |
| Partial Contour Fort | ✗ |
| Promontory Fort | ✓ |
| Hillslope Fort | ✗ |
| Level Terrain Fort | ✗ |
| Marsh Fort | ✗ |
| Multiple Enclosure Fort | ✗ |
| Hilltop | ✗ |
| Coastal Promontory | ✓ |
| Inland Promontory | ✗ |
| Valley Bottom | ✗ |
| Knoll/Hillock/Outcrop | ✗ |
| Ridge | ✗ |
| Cliff/Plateau-edge/Scarp | ✗ |
| Hillslope | ✗ |
| Lowland | ✗ |
| Spur | ✗ |
Dominant Topographic Feature: None
| North | ✗ |
| Northeast | ✓ |
| East | ✗ |
| Southeast | ✗ |
| South | ✗ |
| Southwest | ✗ |
| West | ✗ |
| Northwest | ✗ |
| Level | ✗ |
Altitude: 15.0m
N/A
There is no dating available for the site
Reliability: D - None
| Pre 1200BC | ✗ |
| 1200BC - 800BC | ✗ |
| 800BC - 400BC | ✗ |
| 400BC - AD50 | ✗ |
| AD50 - AD400 | ✗ |
| AD400 - AD 800 | ✗ |
| Post AD800 | ✗ |
| Unknown | ✓ |
| Pre Hillfort: | None |
| Post Hillfort: | None |
The site is marked as 'Horse Island' on the first edition OS six-inch map (1839). Surveyed by Thomas Westropp in 1912 who noted the remains of a wall.
| 1st Identified Map Depiction (1839): | OS six-inch maps |
| 1st Identified Written Reference (1914): | Thomas Westropp |
There are no recorded internal features
None
| None | ✓ |
| Spring | ✗ |
| Stream | ✗ |
| Pool | ✗ |
| Flush | ✗ |
| Well | ✗ |
| Other | ✗ |
None
| No Known Features | ✓ |
| Round Stone Structures | ✗ |
| Rectangular Stone Structures | ✗ |
| Curvilinear Platforms | ✗ |
| Other Roundhouse Evidence | ✗ |
| Pits | ✗ |
| Quarry Hollows | ✗ |
| Other | ✗ |
None
| No Known Excavation | ✓ |
| Pits | ✗ |
| Postholes | ✗ |
| Roundhouses | ✗ |
| Rectangular Structures | ✗ |
| Roads/Tracks | ✗ |
| Quarry Hollows | ✗ |
| Other | ✗ |
| Nothing Found | ✗ |
None
| No Known Geophysics | ✓ |
| Pits | ✗ |
| Roundhouses | ✗ |
| Rectangular Structures | ✗ |
| Roads/Tracks | ✗ |
| Quarry Hollows | ✗ |
| Other | ✗ |
| Nothing Found | ✗ |
None
| No Known Finds | ✓ |
| Pottery | ✗ |
| Metal | ✗ |
| Metalworking | ✗ |
| Human Bones | ✗ |
| Animal Bones | ✗ |
| Lithics | ✗ |
| Environmental | ✗ |
| Other | ✗ |
NO APPARENT FEATURES
| APs Not Checked | ✓ |
| None | ✗ |
| Roundhouses | ✗ |
| Rectangular Structures | ✗ |
| Pits | ✗ |
| Postholes | ✗ |
| Roads/Tracks | ✗ |
| Other | ✗ |
There are no recorded entrances. The Island was probably accessed via a narrow causeway which has since fallen into the sea, isolating the landmass.
| 0: | None |
| 2: | None |
Guard Chambers: ✗
Chevaux de Frise: ✗
Westropp records the remains of a wall 'at the head of the slope, foundation blocks, in line, and in places, a few courses high' (1912, 120). He observed that the wall was 'ready to slide down if the shaken bank gives way below'. Unfortunately, no other information is available as to the composition of this wall
| Area 1: | 4.78ha. |
| Total: | 4.78ha. |
Total Footprint Area: 4.78ha.
None
| ✗ | None |
| ✗ | None |
| NE Quadrant: | 0 |
| SE Quadrant: | 0 |
| SW Quadrant: | 1 |
| NW Quadrant: | 0 |
| Total: | 1 |
| Partial Univallate | ✓ |
| Univallate | ✗ |
| Partial Bivallate | ✗ |
| Bivallate | ✗ |
| Partial Multivallate | ✗ |
| Multivallate | ✗ |
| Unknown | ✗ |
| Partial Univallate | ✗ |
| Univallate | ✗ |
| Partial Bivallate | ✗ |
| Bivallate | ✗ |
| Partial Multivallate | ✗ |
| Multivallate | ✗ |
None
| None | ✗ |
| Earthen Bank | ✗ |
| Stone Wall | ✓ |
| Rubble | ✗ |
| Wall-walk | ✗ |
| Evidence of Timber | ✗ |
| Vitrification | ✗ |
| Other Burning | ✗ |
| Palisade | ✗ |
| Counter Scarp Bank | ✗ |
| Berm | ✗ |
| Unfinished | ✗ |
| Other | ✗ |
None
| None | ✗ |
| Earthen Bank | ✗ |
| Stone Wall | ✗ |
| Murus Duplex | ✗ |
| Timber-framed | ✗ |
| Timber-laced | ✗ |
| Vitrification | ✗ |
| Other Burning | ✗ |
| Palisade | ✗ |
| Counter Scarp Bank | ✗ |
| Berm | ✗ |
| Unfinished | ✗ |
| No Known Excavation | ✓ |
| Other | ✗ |
| ✗ | None |
| ✗ | None |
Number of Ditches: 0
| ✗ | None |
Westropp, T.J. 1912. The promontory forts and early remains of the coasts of County Mayo. Part 1- The north coast (Tirawley and Erris). The Journal of the Royal Society of Antiquaries of Ireland 42, 59-139
Atlas of Hillforts:
Wikidata:
This work is licensed under CC BY-SA 4.0
and should be cited as:
Lock, Gary and Ralston, Ian. 2024. Atlas of Hillforts of Britain and Ireland. Available at: https://hillforts.arch.ox.ac.uk
Document Version 1.1