The `邮局` in China is almost exclusively synonymous with 中国邮政 (Zhōngguó Yóuzhèng), or China Post. It's a massive state-owned enterprise, recognizable by its iconic dark green branding. Unlike the USPS in America, which primarily focuses on mail and has faced financial struggles, China Post is a sprawling entity with deep integration into Chinese society. Its most significant difference is its banking arm: the Postal Savings Bank of China (中国邮政储蓄银行). Nearly every `邮局`, especially in smaller towns and rural areas, is co-located with one of these banks. For many older Chinese people and those in less-developed regions, the local `邮局` is also their primary bank for savings, transfers, and paying utility bills. In the modern era of e-commerce, China Post's role in parcel delivery has been challenged by hyper-efficient private courier companies (快递公司, kuàidì gōngsī) like SF Express (顺丰) and the network used by Alibaba, Cainiao (菜鸟). For most urban residents, sending a package via a private courier is faster and more convenient. However, the `邮局` is still seen as the most reliable (if slower) option for sending important documents, international mail, and for its unparalleled reach into every corner of the country.
In daily conversation, you'll use `邮局` just like you use “post office” in English. You go there to send things.
The most common point of confusion for learners is the difference between 邮局 (yóujú) and 快递 (kuàidì).
Common Mistake: Do not refer to the office of a private courier company as a `邮局`. For example, SF Express (顺丰速运) is a `快递公司` (courier company), and its local branch is a `站点` (zhàndiǎn - station/point), not a `邮局`.
Think of it this way: `邮局` is like “The Post Office” (a proper name for an institution), while `快递` is like “courier service” (a generic term).