California Code, Fish and Game Code - FGC § 1779

(a) A geographical area having a population of 50,000 or more inhabitants within the jurisdiction of a city, or a town, as defined by Sections 20 and 21 of the Government Code.

(b) A portion of any geographical area within a town, as defined in Section 21 of the Government Code, which has a population density equal to, or exceeding, 1,500 persons per square mile and which has a population of 50,000 or more inhabitants.

(c) A geographical area having a population density equal to, or exceeding, 1,500 persons per square mile, and an adjacent city, as defined in Section 20 of the Government Code, where the combined population of the geographical area and the city equals 50,000 or more inhabitants.

(d) A geographical area within the sphere of influence of a city or community services district for which the projected population of the adopted general plan equals 10,000 or more inhabitants.