"a headquarters" or just "headquarters"?

Question

Source: Russia Pounds ISIS With Biggest Bomber Raid in Decades

Example:

Russian officials notified U.S. planners at a coalition headquarters in Qatar before the strike, Pentagon spokesman Peter Cook said. It was the first time the Russians and Americans have put into action an October agreement to coordinate their countries' respective operations in Syria.

Do you think it's grammatically correct to say a headquarters? The word has a define plural sense to it. Generally, it feels absolutely weird to use an indefinite article in front of a word that ends in s. And it should be because the s marker makes an idea or thing plural, whereas an indefinite article denotes the fact that we only have one of something. Is this an exception to the rule? How do you native speakers actually reconcile this problem? Is this something that you find strange too?

Answer 1

'Headquarters' mean the main offices of any organization. Ideally, it is the central office and in most of the cases, it is one and the only. Said that, we find more use of 'the headquarters' as compared to 'a headquarters'.

Now, can it take the indefinite article 'a'? Yes, it can. How? Because 'headquarters' can serve as singular and plural both.

The company's headquarters is in Mumbai - is absolutely fine.

So, in the given sentence, 'a coalition headquarters in Qatar' is fine.

COCA shows several examples of 'a headquarters'. Yes, it's not incorrect.

Answer 2

There are some limited contexts in which "a headquarters" is a correct usage, albeit with a classifier between the article and the noun. For instance, "A corporate headquarters in Palookaville was robbed last night." Mind you that this sentence only makes sense if spoken of the headquarters of an unknown or generic corporation. An employee of the corporation would say, "Corporate headquarters was robbed last night" or "Our corporate headquarters was robbed last night", but it would make no sense for him to say "A corporate headquarters". However, in the particular context of your quote it's almost certainly wrong. The headquarters being discussed belongs to a known entity, be that the "Warmongering Coalition", the "Friends of ISIS Coalition" or some other coalition, and that entity is presumably headquartered in one single place, not several, which is implied by the employment of the indefinite article in relation to this particular headquarters. Correct and clear usage would have been, "Russian officials notified U.S. planners at coalition headquarters in Qatar." Alternately, it could have been, "Russian officials notified U.S. planners at the headquarters of the coalition in Qatar." However, this second version isn't any more clear while being longer, so the first one is preferable.