The Humans of Stormwind and Stromgarde comprise the bulk of the Arathor Kingdom.
It is all that remains of the once great Arathor Empire, which covered most of the southern Eastern Kingdoms.
It was a member of the Great Alliance during the second war, though relations with the other members have deteriorated since then.
Stormwind is located in the south of the Eastern Kingdoms, with a portal leading to Outland at the south east area of your lands.
Dwarves - Ironforge, the capital of the Dwarves, and his main forces, are located north east of your capital, in Khaz Modan. You should cooperate with him and try to work together at all times to overcome your enemies. Dwarves also have a small settlement inside Stormwind itself, allowing for some quick aid if needed. Further more, developing the Deeprum Tram will allow instant transport between Stormwind and Ironforge.
Arathor Kingdom is loosely based on the real lore of the Warcraft universe at the time of the Third War, as the Kingdom of Azeroth (AKA Arathor Kingdom) did not played any role in the Third War, but in the Second, and in WoW's lore following the onslaught of the Undead Scourge.