LiDAR 1m DTM Hillshade
Satellite Imagery
LiDAR 1m DTM Hillshade
Satellite Imagery
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HER: Gwynedd 767 (None)
NMR: None (95305)
SM: CN045
NGR: SH18702846
X: 218700 Y: 328460 (OSGB36)
Small contour hillfort located on summit of Mynydd Ystum on W tip of Ll_n Peninsula. Moderate to strong surrounding slopes. Sub-circular measuring 50m to 56m diameter, with internal area 0.2ha. Defined by two concentric encircling ramparts separated by c. 15m. Where best stand to c. 1.5m high externally. Simple entrance on NE. Outer first an earthen bank then revetted in stone. Inner revetted with boulders possibly contemporary with later outer bank. Both now reduced to scarps. No ditch. At least eight huts in interior, with possibly two more, c. 7.5m diameter. Site dismantled, possibly in Roman period. Extensive excavations, by C.E. Breese c. 1930 and L. Alcock 1958-9, showed lengthy occupation sequence from late Bronze Age to Roman period. Supplementary excavation of bank produced charcoal. Some C14 dates 800-200 cal BC from below outer rampart. Pillow mound within enclosure c. 17m by 4.5m surrounded by low bank. Rough pasture and scrub. Banks now reduced to scarps. On 1st Ed. OS map (1885-1900).
Citizen Science: ✗
Reliability of Data: Confirmed
Reliability of Interpretation: Confirmed
X: -522337 Y: 6950339 (EPSG: 3857)
Longitude: -4.692228937428452 Latitude: 52.823079021756385 (EPSG:4326)
Country: Wales
Current County or Unitary Authority: Gwynedd
Historic County: Caernarfonshire
Current Parish/Community/Council/Townland: Aberdaron
Banks now largely reduced to scarps.
| Extant | ✓ |
| Cropmark | ✗ |
| Likely Destroyed | ✗ |
Rough upland grazing and scrub, less to N and E.
| Woodland | ✗ |
| Commercial Forestry Plantation | ✗ |
| Parkland | ✗ |
| Pasture (Grazing) | ✓ |
| Arable | ✗ |
| Scrub/Bracken | ✓ |
| Bare Outcrop | ✗ |
| Heather/Moorland | ✗ |
| Heath | ✗ |
| Built-up | ✗ |
| Coastal Grassland | ✗ |
| Other | ✗ |
Small contour hillfort located on summit of Mynydd Ystum on W tip of Ll_n Peninsula. Moderate to strong surrounding slopes. Subcircular
| 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: Hill top
| North | ✗ |
| Northeast | ✗ |
| East | ✗ |
| Southeast | ✗ |
| South | ✗ |
| Southwest | ✗ |
| West | ✗ |
| Northwest | ✗ |
| Level | ✓ |
Altitude: 146.0m
N/A
Extensive excavations, by Breese c. 1930 and Alcock 1958-9, showed lengthy occupation sequence from late Bronze Age to Roman period. Late Bronze Age pottery found from earliest phase, though date much disputed in past. C14 dates of 800-200 cal BC from below outer rampart.
Reliability: B - Medium
| Pre 1200BC | ✗ |
| 1200BC - 800BC | ✗ |
| 800BC - 400BC | ✓ |
| 400BC - AD50 | ✓ |
| AD50 - AD400 | ✓ |
| AD400 - AD 800 | ✗ |
| Post AD800 | ✗ |
| Unknown | ✗ |
| Pre Hillfort: | None |
| Post Hillfort: | None |
| Artefactual: | Later Bronze Age pottery found from earliest phase. |
| C14: | Dates from below outer rampart. |
On 1st Ed. OS map (1885-1900). Excavation by C.E. Breese c. 1930. Excavation L. Alcock 1958-59. Supplementary excavation of bank - no details. GAT prehistoric defended enclosures survey 2005-2006.
| Other (2005): | Visited by Hillfort Study Group |
| 1st Identified Map Depiction (None): | OS map. |
| Excavation (None): | L. Alcock |
| Other (None): | GAT prehistoric defended enclosures survey. |
| Excavation (None): | C.E. Breese. |
| Excavation (None): | Supplementary excavation of bank. |
At least eight huts in interior; possibly two more. Pillow mound within enclosure c. 17m by 4.5m surrounded by low bank.
Afon Daron 0.6 km outside fort.
| None | ✓ |
| Spring | ✗ |
| Stream | ✗ |
| Pool | ✗ |
| Flush | ✗ |
| Well | ✗ |
| Other | ✗ |
At least eight huts in interior; possibly two more. Pillow mound within enclosure c. 17m by 4.5m surrounded by low bank.
| No Known Features | ✗ |
| Round Stone Structures | ✗ |
| Rectangular Stone Structures | ✗ |
| Curvilinear Platforms | ✗ |
| Other Roundhouse Evidence | ✓ |
| Pits | ✗ |
| Quarry Hollows | ✗ |
| Other | ✓ |
At least eight huts in interior; possibly two more.
| 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 | ✗ |
Later Bronze Age pottery and charcoal found. Excavations showed lengthy occupation sequence.
| No Known Finds | ✗ |
| Pottery | ✓ |
| Metal | ✗ |
| Metalworking | ✗ |
| Human Bones | ✗ |
| Animal Bones | ✗ |
| Lithics | ✗ |
| Environmental | ✓ |
| Other | ✗ |
None
| APs Not Checked | ✓ |
| None | ✗ |
| Roundhouses | ✗ |
| Rectangular Structures | ✗ |
| Pits | ✗ |
| Postholes | ✗ |
| Roads/Tracks | ✗ |
| Other | ✗ |
Simple gap entrance on NE.
| 1: | None |
| 2: | None |
Guard Chambers: ✗
Chevaux de Frise: ✗
| 1. Simple Gap (North east): | None |
Defined by two concentric encircling ramparts separated by c. 15m. Where best stand to c. 1.5m high externally. Outer first an earthen bank then revetted in stone. Inner revetted with boulders possibly contemporary with later outer bank. Both now reduced to scarps. Site dismantled, possibly in Roman period. No ditch. 02.ha.
| Area 1: | 0.2ha. |
| Total: | 0.2ha. |
Total Footprint Area: Noneha.
None
| ✗ | None |
| ✓ | Ramparts separated by 15m interval. |
| NE Quadrant: | 2 |
| SE Quadrant: | 2 |
| SW Quadrant: | 2 |
| NW Quadrant: | 2 |
| Total: | 2 |
| Partial Univallate | ✗ |
| Univallate | ✗ |
| Partial Bivallate | ✗ |
| Bivallate | ✓ |
| Partial Multivallate | ✗ |
| Multivallate | ✗ |
| Unknown | ✗ |
| Partial Univallate | ✗ |
| Univallate | ✗ |
| Partial Bivallate | ✗ |
| Bivallate | ✗ |
| Partial Multivallate | ✗ |
| Multivallate | ✗ |
Shows as earthen banks.
| None | ✗ |
| Earthen Bank | ✓ |
| Stone Wall | ✗ |
| Rubble | ✗ |
| Wall-walk | ✗ |
| Evidence of Timber | ✗ |
| Vitrification | ✗ |
| Other Burning | ✗ |
| Palisade | ✗ |
| Counter Scarp Bank | ✗ |
| Berm | ✗ |
| Unfinished | ✗ |
| Other | ✗ |
Evidence of palisade. Outer first an earthen bank then revetted in stone. Inner revetted with boulders possibly contemporary with later outer bank. Site dismantled, possibly in Roman period.
| 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 |
Alcock, L. 1960. Castell Odo. An embanked settlement on Mynydd Ystum, near Aberdaron, Caernarvonshire, Arch Camb, 109, 78-135.
Breese , C.E.1933. Castell Odo, Arch Camb, 87, 372-85.
Houlder, C. 1978. Wales an archaeological guide, London: Faber and Faber, 48-9.
Lynch, F. 1995. A guide to ancient and historic Wales - Gwynedd, London: HMSO, 78-80.
Smith, G.H. 2006. A survey of prehistoric defended enclosures in north-west Wales 2005-2006: Gwynedd Dwyfor and Meirionnydd. Report No 634. Part I: Survey Report. Bangor: Gwynedd Archaeological Trust.
Waddington, K. 2013. The Settlements of Northwest Wales: From the Late Bronze Age to the Early Medieval Period, Cardiff: University of Wales Press.
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