A city may acquire, by purchase or eminent domain, property outside its boundaries in the unincorporated area of the county in which the city is located, if it is necessary to connect or widen the existing streets of the acquiring city and if the county consents to the acquisition.
The portion of the acquired property used to connect or widen a city street shall be deemed a city street for all purposes.
Ca. Sts. and High. Code § 1810