Llanerchymedd link for genuki gives list of churches in that area
https://www.genuki.org.uk/big/wal/AGY/LlanerchymeddHer father Hugh William’s place of birth given as
Llantrisant Anglesey on 1881 census
https://www.genuki.org.uk/big/wal/AGY/Llantrisaint is 4 miles (W) from Llanerchymedd
on the map of Llantrisaint I noticed the
place name Elim 
Might this be a possibility
Elizabeth Williams Birth 4 Sep 1823
Baptism 11 Sep 1823
Baptism Place:
Elim Calvinistic Methodist, Pentraeth, Anglesey, Wales
Father:
Hugh Williams, farmer Mother:
Elizabeth RobertsThere are also these two other baptisms same place same parents names, so not sure if it's the same Elizabeth with father Hugh from 1881 census
Abode Tydynybwn? Father’s parish Pentraeth, father’s parish before marriage Llanllyfni on all three baptism records
Richard WmsBirth Date: 8 Sep 1824
Birth Place: Pentraeth, Anglesey, Wales
Baptism Date: 12 Sep 1824
Baptism Place: Beaumaris, Anglesey, Wales
Denomination: Calvinistic Methodist
Father:
Hugh Wms, farmer Mother:
Elizabeth RobertsRobert Williams
Birth Date: 28 Nov 1828
Birth Place: Pentraeth, Anglesey, Wales
Baptism Date: 2 Dec 1828
Baptism Place: Beaumaris, Anglesey, Wales
Denomination: Calvinistic Methodist
Father:
Hugh Williams,
farmer Mother:
Elizabeth RobertsEngland & Wales, Non-Conformist and Non-Parochial Registers, 1567-1936Edit to add possible marriage
Hugh WilliamsMarriage 29 Oct 1819 Pentraeth, Anglesey, Wales
Spouse:
Elizabeth Roberts - made her mark (x)
both single, both of this parish ,in the presence of John Owen & Thomas Thomas
or this one perhaps
Hugh Williams of the parish of Pentraeth
Marriage 22 May 1822 Penmynydd, Anglesey, Wales
Spouse:
Elizabeth Roberts - made her mark (x)
both single, in the presence of Richard Williams & Robert Griffith
