Y gwahaniaeth rhwng diwygiadau o "Sir Forgannwg (etholaeth seneddol)"

dim crynodeb golygu
(ASau 1541-1832)
|}
 
=== 1832-1885 ===
{| class="wikitable"
|-
!Blwyddyn!!colspan="2"|Aelod!!Plaid!!colspan="2"|Aelod!!Plaid
|-
| 1832
|rowspan="4" style="background-color: {{Liberal Party (UK)/meta/color}}" |
|rowspan="4"| [[Christopher Rice Mansel Talbot]]
|rowspan="4"| [[Y Blaid Ryddfydol (DU)| Rhyddfrydol]]
|style="background-color: {{/meta/color}}" |
| [[Lewis Weston Dillwyn]]
| <!-- party -->
|-
| 1837
|style="background-color: {{/meta/color}}" |
| [[Edwin Wyndham-Quin]]
| <!-- party -->
|-
| 1851
|style="background-color: {{/meta/color}}" |
| [[George Tyler]]
| <!-- party -->
|-
| 1857
|style="background-color: {{/meta/color}}" |
| [[Henry Hussey Vivian]]
| <!-- party -->
|-
| [[1885]]
|colspan="6"| ''Diddymu'r etholaeth