The term 公安局 (gōng ān jú) literally combines three characters: 公 (gōng, 'public'), 安 (ān, 'safety' or 'security'), and 局 (jú, 'bureau' or 'office'). Together, it designates the local Public Security Bureau—the primary law enforcement agency at the county, city, or provincial level in China. It handles routine policing duties such as crime investigation, traffic control, household registration (hùkǒu), ID issuance, and maintaining public order.

Unlike national agencies like the Ministry of Public Security (公安部), which sets policy, local 公安局 offices operate under dual leadership—reporting both to higher-level public security authorities and to their respective local governments. The term is formal and administrative; you’ll see it on official buildings, documents, and police vehicles. It’s not used in casual speech to refer to individual officers (who are typically called 警察 or 警员), but rather to the institution itself.