New and old

When 2 city names use the same base origin, one is usually named New Something. Districts are usually unofficially called Old Something and the name eventually sticks from common usage. In Chinese, one American city was unofficially called Old Gold Mountain (舊金山) and eventually became the official Chinese name used in China for this American city. 舊金山 is used in most archived/indexed web content, official documents, and online translator dictionaries. That city is of course San Francisco. Online translators also recognize Francisco to mean San Francisco.