weiwei,

I don't know where you got that info from but "城关" is the town itself, not the outside of it. The outside of it is "城郊" which, as you know, is also called the suburbs.

I know that for sure because I travel a lot even before I left China. And a small city or a town is often called "城关镇", especially if it serves as a county seat 县城所在地. The county may have several smaller towns within its jurisdiction, but the 城关镇 would most likely be the 县委所在地。 Police precincts in the smaller towns are actually branches of the County Sheriff's Department (县公安局). While the Sheriff's Department overseeing all the smaller branches (派出所) is siturated in the county seat (or 城关镇), the township (城关镇) itself has a branch too (= its own precinct).

To understand that, just think that Nanjing is the capital of Jiangsu Province where the provincial government is located, but the city of Nanjing has its own municipal government and office establishments and such, though on a lower level.

Now back to the "城关派出所", this form "城关" is an abbreviation, it should be XX城关镇. Just like when the people around Chicago say I am going into the city tommorrow, and "the city" here means Chicago. The same word "city" means San Francisco to those folks here where I am at. So, there is usually a name in front of it which the locals do not bother to say it in full.

Finally, "城关派出所" should be translated as XX Township Police Precinct.

Check Google and you will find lots of XX城关镇 all over China. But in recent years, with the economic expansion, most old 城关镇 or townships of any decent size prefer to call themselves "CITY"! Sure, why not?