Etholaethau'r Deyrnas Unedig

Yr enw am ardal etholiad yn y Deyrnas Unedig yw etholaeth; mae pob etholaeth yn dewis un neu fwy o aelodau senedd neu gynulliad.

Mae pump corff cenedlaethol a gaiff ei ethol gan etholaeth yn y Deyrnas Unedig:
 Tŷ'r Cyffredin (gweler Rhestr etholaethau Seneddol y Deyrnas Unedig)
 Senedd yr Alban (gweler Rhestr etholaethau Senedd yr Alban)
 Cynulliad Gogledd Iwerddon (gweler Rhestr etholaethau Cynulliad Gogledd Iwerddon)
 Cynulliad Cenedlaethol Cymru (gweler Etholaethau a Rhanbarthau etholiadol Senedd Cymru)
 Cynulliad Llundain (gweler Rhestr etholaethau Cynulliad Llundain)

Cyn Brexit yn 2020, defnyddid etholaethau rhanbarthol ar gyfer etholiadau i Senedd Ewrop. (Gweler Rhestr etholaethau Senedd Ewrop.) 

Yn etholiadau llywodraeth leol, gelwir rhanbarthau etholiadol yn ward neu'n ranbarth etholiadol.

 Etholaethau sirol a bwrdeistrefol 
Mae etholaethau'r Tŷ'r Cyffredin, Senedd yr Alban a Chynulliad Cenedlaethol Cymru i gyd wedi eu dynodi ynteu'n etholaeth sirol neu'n etholaeth fwrdeistrefol, ("borough", heblaw yn yr Alban lle defnyddir y gair burgh yn hytrach na borough). Mae etholaethau bwrdeistrefol yn rai trefol yn bennaf. Dyma yw olynydd yr bwrdeistrefi seneddol hanesyddol. (Roedd pob burgh yn yr Alban, heblaw un, yn rhan o etholaeth ardal o fwrdeistrefi. Yr eithriad oedd burgh Caeredin, a oedd hefyd yn etholaeth Caeredin yn ei hun.)

Etholaethau sirol yw'r olynwyr i'r rhanbarthau seneddol o siroedd: maent yn bennaf yn ardaloedd gwledig. Weithiau, gall tref gael ei rannu rhwng sawl etholaeth, gydag un rhan y fwrdeistref mewn un etholaeth ac un arall mewn etholaeth gwahanol: er enghraifft, Reading a Milton Keynes.

Mae'r cyfyngiadau gwario ar gyfer y ddwy fath o etholaeth ar gyfer ymgyrch etholiad yn wahanol, gan fod yn rhaid i ymgeiswyr mewn etholaethau gwledig deithio'n bellach fel arfer.
{| class="prettytable"
!rowspan="2"| Elected body !!colspan="2"|Constituency type
|-
! bwrdeistref/burgh !! sir
|-
|House of Commons
|| £7,150 + 5p per elector || £7,150 + 7p per elector
|-
|Northern Ireland Assembly || £5,483 + 4.6p per elector || £5,483 + 6.2p per elector
|-
|'Scottish Parliament Welsh Assembly ||  £5,761 + 4.8p per elector || £5,761 + 6.5p per elector
|}

For by-elections to any of these bodies, the limit in all constituencies is £100,000.

 House of Commons constituencies 

As of the 2005 United Kingdom general election, the House of Commons has 646 constituencies covering the whole of the United Kingdom. Each constituency elects one Member of Parliament (MP) by the "first past the post" system of election.

The House of Commons is one of the two legislative bodies of the Parliament of the United Kingdom, the other being the House of Lords.

 See also 
 List of United Kingdom Parliament constituencies
 Former United Kingdom Parliament constituencies
 Constituencies in the next United Kingdom general election
 University constituency

 London Assembly constituencies 

There are fourteen London Assembly constituencies covering the Greater London area, and each constituency elects one member of the assembly by the first past the post system of election. Also, eleven additional members are elected from Greater London as a whole to produce a form or degree of mixed member proportional representation.

Constituency names and boundaries remain now as they were for the first general election of the assembly, in 2000.

The assembly is part of the Greater London Authority and general elections of the assembly are held at the same time as election of the Mayor of London.

 Northern Ireland Assembly constituencies 

 Scottish Parliament constituencies 

Scottish Parliament constituencies are sometimes called Holyrood constituencies, to distinguish them from Westminster'' (House of Commons) constituencies. The Scottish Parliament Building is in the Holyrood area of Edinburgh, while the main meeting place of the Parliament of the United Kingdom is the Palace of Westminster, in the City of Westminster.

There are 73 Holyrood constituencies covering Scotland, and each elects one Member of the Scottish Parliament (MSP) by the first past the post system of election. Also, the constituencies are grouped into eight electoral regions, and each of these regions elects seven additional members, to produce a form or degree of mixed member proportional representation.

The existing constituencies were created, effectively, for the first general election of the Scottish Parliament, in 1999. When created, all but two had the names and boundaries of Westminster constituencies. The two exceptions were the Orkney Holyrood constituency, covering the Orkney Islands council area, and the Shetland Holyrood constituency, covering the Shetland Islands council area. For Westminster elections, these council areas were covered (and still are covered) by the Orkney and Shetland Westminster constituency.

In 1999, under the Scotland Act 1998,Scotland Act 1998, Office of Public Sector Information website the expectation was that there would be a permanent link between the boundaries of Holyrood constituencies and those of Westminster constituencies. This link was broken, however, by the Scottish Parliament (Constituencies) Act 2004,Scottish Parliament (Constituencies) Act 2004, Office of Public Sector Information website which enabled the creation of a new set of Westminster constituencies without change to Holyrood constituencies. The new Westminster boundaries became effective for the United Kingdom general election, 2005.

Etholaethau Cynulliad Cenedlaethol Cymru

Mae 40 etholaeth Cynulliad Cenedlaethol Cymru ar draws Gymru, ac mae pob un yn ethol un Aelod Cynulliad gan ddefnyddio system etholaeth cyntaf heibio i'r post. Caiff yr etholaethau hefyd eu grŵpio'n bedwar ardal etholaethol, ac mae pob ardal yn ethol aelodau ychwanegol, er mwyn ffurfio rhyw fath o gynyrchioliad cyfrannol aelodau cymysg.

Mae gan etholaethau'r cynulliad yr un enwau a etholaethau'r Tŷ Cyffredin, ond yn 2007, crewyd set newydd o etholaethauThe Parliamentary Constituencies and Assembly Electoral Regions (Wales) Order 2006, "Office of Public Sector Information" ar gyfer Etholiad Cynulliad Cenedlaethol Cymru, 2007.

Y set cyfredol o etholaethau'r Cynulliad yw'r ail i gael ei greu. Crewyd y cyntaf ar gyfer etholiad cyntaf y Cynulliad ym 1999.

 Etholaethau Senedd Ewrop 
Mae deuddeg o Etholaethau Senedd Ewrop yn y Deyrnas Unedig. Mae pob un heblaw un wedi'u lleoli yn gyfan gwbl o fewn y Deyrnas Unedig. Yr eithriad yw etholaeth De-orllewin Lloegr, sy'n cynnwys Gibraltar. Mae pob etholaeth yn ethol sawl Aelod Senedd Ewrop (ASE) gan ddefnyddio dull d'Hondt o gynyrchioliad cyfrannol rhestr-plaid.

Defnyddiwyd y set gyfredol o etholaethau Senedd Ewrop y DU yn Etholiad Senedd Ewrop 1999 pan etholwyd Aelodau Senedd Ewrop ar gyfer y Deyrnas Unedig 2009-2014.

Cyfeiriadau


Categori:Gwleidyddiaeth y Deyrnas Unedig