noun
conservation area; preservation district
Refers to a legally designated area where historical buildings, natural landscapes, or cultural assets are protected from development.
この町の保存地区では、古い町並みが大切に守られている。
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.
Compound of 保存 (preservation) and 地区 (district, area).