3 Erw Nantyderi (Field).
Grid Reference: SN 96565 07754. Parish: Penderyn, Brecknockshire
When recorded: 1841. Primary Source: none. Secondary Source: Cynefin

Afon Deri (Unclassified).
Grid Reference: SH 73639 08961. Parish: Tal-y-llyn, Merionethshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Afon Deri (Unclassified).
Grid Reference: SH 75072 07913. Parish: Tal-y-llyn, Merionethshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Afon Gwidderig (Unclassified).
Grid Reference: SN 80262 34956. Parish: Llanfair-ar-y-bryn, Carmarthenshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Afon Gwydderia (Unclassified).
Grid Reference: SN 82383 33312. Parish: Llanfair-ar-y-bryn, Carmarthenshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Afon Gwydderig (Unclassified).
Grid Reference: SN 78474 34556. Parish: Llandingad Without, Carmarthenshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Allt Maderin (Unclassified).
Grid Reference: SH 60454 52824. Parish: Betws Garmon, Caernarfonshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Allt Pen-deri (Topographic feature).
Grid Reference: SN 54258 06436. Parish: Llannon, Carmarthenshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Allt y Deri (Topographic feature).
Grid Reference: SN 41892 31553. Parish: Llanpumsaint, Carmarthenshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Bedw deri (Field).
Grid Reference: SN 98553 48501. Parish: Llanynys, Brecknockshire
When recorded: 1841. Primary Source: none. Secondary Source: Cynefin