The westernmost of the three Kazakh hordes that emerged as a self-governing khanate after the Kazakh Khanate fragmented following Tayke (Tauke) Khan's death; under Abulkhair Khan it was the first jüz to accept Russian protection (1731), and the first whose khanship Russia abolished.
Khanate abolished by the Russian Empire in 1824 (Charter on the Orenburg Kirghiz); territory absorbed into the Orenburg administration. Not an ending of the Kazakh people, who continue.
Standard English history charting the three-jüz structure, the 1731 Russian protectorate, and the 1820s abolition of the khanates (Hoover Institution Press).
Concise scholarly framing of the Kazakh hordes and the Russian advance (New Oxford World History).