Please replace the old information with up to date information.
- This may include rewriting sections to ensure they are clear and concise, and wikifying.
Reason: Not up-to-date as of Jan 2012.
In Patch 3.3.0 cross realm instances were introduced, and they are connected in the same groups as the battlegrounds.
With the introduction of World of Warcraft: Cataclysm and Rated battlegrounds, battlegroups no longer apply to battlegrounds. Players from different battlegroups can PvP against each other in both random and rated battlegrounds if they are in the same region (US, EU, etc.).
1 US 1.1 Notes
Though there is not a current official page dedicated to the North American battlegroups as of yet, players can go Rated Battlegrounds Ladder (US) or Rated Battlegrounds Ladder (EU) and use the drop-down menu to select battlegroups for the rated battlegrounds. Hitting 'filter' will then show the realms listed for that battlegroup, regardless of whether there are any players from those realms engaged in the rated battlegrounds.
EU Battlegroups (English)
EU Battlegroups (German)
EU Battlegroups (Cross-Languages)
EN English language servers ES Spanish language servers
EU Battlegroups (Russian)
^ Mumper 2010-11-18. Rated Extreme mining FAQ. Official World of Warcraft Community site (US).
^ Blizzard Entertainment 2010-11-10. Region Wide Battlegroup Matching. Official World of Warcraft Community site (EU).