conservation area; preservation district
Refers to a legally designated area where historical buildings, natural landscapes, or cultural assets are protected from development.
In this town's preservation district, the old streetscape is carefully protected.
保護区 is a broader term for a protected area (often for nature or wildlife), while 保存地区 specifically emphasizes preservation of cultural or historical assets.
traditional architectures preservation district; historic building preservation area
Compound of 保存 (preservation) and 地区 (district, area).