Using at/on/in to describe locations

Which of the following location statements is correct: the old Police Station at Hollywood Road, the old Police Station on Hollywood Road, or the old Police Station in Hollywood Road? If you're uncertain -- or haven't got a clue -- click on 'Read More' for today's blog post!

Recently I was editing a document that had been previously edited by someone else, and came across the following revision referring to

The first writer had written 'on Hollywood Road', but the second writer had changed it to 'at Hollywood Road'.  What's more, another editor suggested that perhaps the expression should be 'in Hollywood Road'! This kind of uncertainty about how to refer to locations is quite widespread in Hong Kong writing, and stems from a deeper uncertainty about the difference in meaning between prepositions. 

There are some basic rules of thumb that can help you decide correctly which preposition to use when you want to describe the spatial location of something. The first thing to remember is that we can think about space in three different ways:

1) somewhere that has no dimensions … we think of it as a point. When we think about space in this way, at is commonly used:

• He lives at 260 King's Road.   [we are thinking of this address as a point in space, with no relevant dimensions]
• I left my bag at the swimming pool.   [here too, the dimensions are irrelevant; we are thinking of the swimming pool purely as an abstract location, and treating it as a point]
  
  

2) somewhere that has one dimension (like a line) or two dimensions (like a surface). When we think about space in this way, on is commonly used:

• There is a Post Office somewhere on Queen's Road.   [we are thinking of Queen's road as a one-dimensional line, with the Post Office located somewhere along this line)
• The sun is shining on Hong Kong this morning.   [we are thinking of Hong Kong as a flat two-dimensional surface]

3) somewhere that has an area with internal space (i.e. with volume), and so has two or three dimensions. When we think about space in this way, in is commonly used:

• The service will take place in St John's Cathedral on Garden Road. [here we are specifically thinking of the cathedral as a three-dimensional place with internal volume -- notice the type #2 preposition 'on' for Garden Road]
• The conference will take place in the Mandarin Hotel in Central.  [here both 'the Mandarin Hotel' and 'Central' are thought of as areas with internal space that is relevant to the content of this sentence]

How then should we write the phrase about the old Police Station? Streets and roads are normally treated as one-dimensional lines, and so typically in standard English you will find them used with the preposition on:

• We have offices on Nathan Road.
• There has been a traffic accident on Mong Kok Road
• You should see the change that's been made to the old Police Station on Hollywood Road

Do be aware, however, that these rules are not hard and fast because it is possible to think about space in different ways in different contexts. Take a look at this sentence, for example:

• She lay down in Hollywood Road and blocked all the traffic

Why 'in Hollywood Road' here? Because in this sentence, Hollywood Road is being treated as a space with internal volume, something you can get 'in'. We understand from this sentence that the woman in question is actually lying in the middle of the road, which means we are thinking of the road as a space with an edge and an interior, an outside and an inside. Hence the use of in a rather than on. 

In summary, the preposition you use to indicate a fixed location in space (at, on or in) depends on how you conceptualise the space you are talking about: as a point (at), a line or flat surface (on), or a space with internal volume (in). Sometimes you can use different prepositions with the same noun, simply because you are conceptualising the space differently.

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