Afon Cwm ystradllyn (Unclassified).
Grid Reference: SH 54275 43123. Parish: Dolbenmaen, Caernarfonshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Afon cwm -ystradllyn (Unclassified).
Grid Reference: SH 52129 42921. Parish: Dolbenmaen, Caernarfonshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Afon Ystrad (Unclassified).
Grid Reference: SJ 07665 65770. Parish: Llanrhaeadr-yng-Nghinmeirch Urban, Denbighshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Afon Ystrad (Unclassified).
Grid Reference: SJ 04635 64982. Parish: Denbigh, Denbighshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Allt yr Ystrad (Unclassified).
Grid Reference: SN 49501 29991. Parish: Llanegwad, Carmarthenshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Allt yr Ystrad (Unclassified).
Grid Reference: SN 49520 29561. Parish: Llanegwad, Carmarthenshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Allt ystrad Walter (Unclassified).
Grid Reference: SN 78853 36333. Parish: Llanfair-ar-y-bryn, Carmarthenshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Avon Ystrad (Topographic feature).
Grid Reference: SH 99273 59684. Parish: Nantglyn, Denbighshire
When recorded: 1699. Primary Source: Parochialia 1. Secondary Source: none

Bane Ystrad-wen (Unclassified).
Grid Reference: SN 98434 61527. Parish: Llanwrthwl, Radnorshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website

Blaen-plwyf-ystrad (Unclassified).
Grid Reference: SN 56829 53648. Parish: Llanfihangel Ystrad, Cardiganshire
When recorded: 1898-1908. Primary Source: OS 2nd Edition Maps. Secondary Source: GB1900 website