Y gwahaniaeth rhwng diwygiadau o "Gorllewin Casnewydd (etholaeth seneddol)"

 
===Canlyniadau Etholiadau yn y 2010au===
 
Bu farw [[Paul Flynn]] ar [[17 Chwefror]] [[2019]] a chynhaliwyd isetholiad i ganfod olynydd iddo ar [[4 Ebrill]] [[2019]]
 
{{Election box begin|title=Isetholiad Gorllewin Casnewydd 2019 2019}}
{{Election box candidate with party link
|party=Plaid Cymru
|candidate=Jonathan Clark
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{{Election box candidate with party link
|party=Renew Party
|candidate=June Davies
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{{Election box candidate with party link
|party=Conservative Party (UK)
|candidate=Matthew Evans
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{{Election box candidate with party link
|party=UK Independence Party
|candidate=[[Neil Hamilton]]
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{{Election box candidate with party link
|party=Labour Party (UK)
|candidate=Ruth Jones
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{{Election box candidate with party link
|party=Liberal Democrats (UK)
|candidate=Ryan Jones
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{{Election box candidate with party link
|party=Y Blaid Ddemocrataidd Gymdeithasol (DU, 1990)
|candidate=Ian McLean
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{{Election box candidate with party link
|party=For Britain
|candidate=Hugh Nicklin
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{{Election box candidate with party link
|party=Diddymu Cynulliad Cymru
|candidate=Richard Suchorzewski
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{{Election box candidate with party link
|party=Democratiaid a chyn-filwyr
|candidate=Philip Taylor
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{{Election box candidate with party link
|party=Green Party of England and Wales
|candidate=[[Amelia Womack]]
|votes=
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{{Election box majority||votes=|percentage=|change=}}
{{Election box turnout||votes=|percentage=|change=}}
{{Election box end}}
 
{{Dechrau bocs etholiad | teitl=[[Etholiad cyffredinol y Deyrnas Unedig, 2017|Etholiad cyffredinol 2017]]: Etholaeth: Gorllewin Casnewydd<ref>Daily Post 10 Mehefin 2017 ''How Wales Voted - results in detail''</ref>