California Code, Government Code - GOV § 38304

The legislative body of any city may lay out, open, construct, maintain, and control all roads, streets, and boulevards necessary or requisite for the purpose of connecting the city with any city-owned public park or playground situated wholly or partly outside of the limits of the city.  For such purpose it may acquire by gift, purchase, or eminent domain any land or rights of way lying between the limits of the city and the exterior limits of the park or playground.