Iaen
Hyaen, Haen 1185 CAYS, no.11, p.152 (Wynnstay) and AWR, no.541, p.746; Yhaen 1226 CAYS, no.68, p.209 (Wynnstay) and AWR, no.282, p.449; Yaen 1530 CamQ I, p.328 (MontC 6, p.361); R. Yale 1833 OSD Machynlleth (337); Afon Ial 1836 OS 1:63,360; Afon Iaen 1887 OS 1:10,560
Afon Glyn Hwrdd 1870 Haul 14, no.163, p.204
Is-y-coed
(t.) Iscoedpenegoes 1555 NLW POWIS/N/12519; (t.) Iskoed Penegoes 1575 NLW POWIS/N/12565; Yskoed Penegoes 1577 NLW WALES 4/128/4, m.25;(t.) Iscoyd Penegos 1596 PowysAMD/HPA/4/3/15; Iscoed, Penegoes 1609: 1608-9 MontC 37, p.524;(t.) Iskoed Pennigoes 1613: 1612-13 EPCJ, p.277;(mess. and walk mill at) Is-y-coed 1634 NLW GOGERDDAN/JAA3/2;(Hugh Griffith Howell of) Iscoed Penegost 1697 NLW Probate SA/1697/197; (t.) Isycoed 1774 recte 1776 PowysA M/Q/R/X/1, p.8
Isygarreg
Issygarreg 1565 NLW POWIS/N/12556; (Jeuan ap Llewis Bedo: place Tale r henbont in t. Isgarregg 1569 NLW Probate SA/1569/R1/152r; Ysygarred 1577 NLW WALES 4/128/4, m.25; Ys-y-garreg 1578 MontR, p.404; (John ap Howell ap Rees: t.) ysse y garege 1585 NLW Probate SA/1585/R5/9v; Iss-garreg 1597 MontC 21, p.220; Ysygarreg c.1620 TNA CP.318/55; 1670 MontC 24, p.209, Isygarreg 1774 Powys AFB, p.8, Is Carreg 1811 CarlisleTD
Bwlch-y-garreg 1578 MontR, p.404. Otherwise recorded as 1887 Bwlch OS 1:10,560
Iwrch
(r.) Yorgh 1600 NLW CHIRK/F/342; Iwrch 1870 Haul 14, no.163, p.204; River Iwrch 1880, Afon Iwrch 1914 OS 1:10,560; (John Edwards of) Moeliwrch 1738 NLW Probate SA/1738/100; Moeliwrch 1880 OS 1:10,560
(brook) Nant Ywrch 1668 BBCS 24, pp. 523 (TNA E179/242/48); T.W. Hancock, in MontC 4, p.212, says Iwrch had a tributary Ewig apparently confirmed by the hill-n. Moel yr Ewig (SJ 076320).