California: Polity Style: 1846-1849

13 Aug 1846	following the invasion of Mexico by the armed forces of the United States, the Pacific Squadron takes possession of Ciudad de los Angeles, temporary seat of government of the Department of the Californias (Departamento de los Californias) on 13 Aug 1846 (United States Congressional Serial Set, 30th Congress, 1st session, House Executive Document No. 60, p. 266; Californian, No. 4, 5 Sep 1846, p. 2)
17 Aug 1846	the Territory of California is declared a possession of the United States in accordance with a proclamation of the Commander-in-Chief and Governor of the Territory of California issued on 17 Aug 1846 at Ciudad de los Angeles (Californian, No. 4, 5 Sep 1846, p. 2) [1]
17 Aug 1846 - 12 Dec 1849	Territory of California :: California
30 May 1848	the territories of Mexico occupied by the armed forces of the United States are incorporated into the United States within the boundaries defined by a treaty concluded by the plenipotentiaries of both nations at Guadalupe Hidalgo, Mexico, on 2 Feb 1848 (effective upon the exchange of ratifications at Querétaro on 30 May 1848) (Statutes at Large, 9:922-943; Correo Nacional, No. 121, 9 Jun 1848, pp. 1-4) [2]
13 Oct 1849	the Constitution of the State of California is adopted at a session of the Constitutional Convention held at Monterey on 11 Oct 1849 and signed by delegates of the Convention on 13 Oct 1849, pending the ratification by the people of California (California Constitutional Convention 1849, pp. 459-461, 476)
12 Dec 1849	the Constitution of the State of California is ratified by the people of California at an election held on 13 Nov 1849, the results of which were certified by a proclamation issued by the Governor of California on 12 Dec 1849, declaring the Constitution established (Alta California, No. 7, 24 Dec 1849, p. 3)

In 1846, the armed forces of the United States occupied northern parts of Mexico, including the northern part of the Departamento de las Californias (formerly the Territorio de Alta California). The occupied area was referred to in the proclamation as the "Territory of California," although it was never formally organized as a territory of the United States under federal law.
The Treaty of Guadalupe Hidalgo did not specifically refer to the occupied territories as a "cession," instead defining new boundaries between Mexico and the United States.