normally when people in the US refer to LA they refer to the
CITY of LA, not various parts of the LA basin or LA county. for
example, the place i stayed at was at the fullerton district in
anaheim in orange county, which is one of the few counties in the
entire LA basin, it is still ok to say that anaheim is part of the
LA basin but u can't say that anaheim is in LA because over there
LA means LA city itself.