The Assyrian Empire
At the maximum extent, including some internal kingdoms that kept their own kings as vassals under Assyrian sovereignty (Urartu-Tilgarimmu, Judah). Other lands outside the Empire had an Assyrian viceroy (Khayappa, Mushri, Dilmun, etc.) but were not considered part of the Empire itself.
Source: Map courtesy of Imninalu.net, cannot be republished without consent from author or AICE.