In an alternate timeline where Khan Noonien Singh was victorious in the Eugenics Wars and Humans underwent genetic engineering en masse, the Khanate of Earth was the interstellar empire of Earth.

Subject races of the Khanate included the Andorians, Vulcans, Trill, Tellarites, Son'a, Ferengi, Betazoids and Bajorans. Andorians enjoyed a special status within the Khanate, whereas Vulcans and Trill were regarded as slave races or helots. Subject races of the Khanate were sometimes offered the option to genetically enhance their populations.

In addition to the above races, the Khanate had fought a devastating war against the Romulans in the 2100s, and had forced the Tzenkethi, Breen and Tholians to all acknowledge the power of Earth and to back down to their own respective territories.

The Khanate was initially ruled by Khan Noonien Singh until his death in 2172. Subsequent rulers were the Khan's immediate descendants. By 2376, his grandson Tiberius Sejanus Singh had become leader. A resistance existed among some of the subject species of the Khanate, including the Trill and Bajorans, and supported by the Cardassians, who had seen their territory hemmed in by the Khanate. (Myriad Universes - Infinity's Prism novella: Seeds of Dissent)