Sentence examples for how close from inspiring English sources

"how close" is correct and commonly used in written English.
It is usually used as an interrogative phrase, meaning it is used to ask a question about the proximity of something or someone. Example: "How close is the nearest grocery store?" This sentence is asking about the distance of the nearest grocery store. Another example: "Can you tell me how close we are to the airport?" This sentence is asking about the proximity of the speaker's current location to the airport.