It is very confusing for students and teachers alike when considering why we use which or where when the antecedent of a relative clause can be thought of as a place: The word where-according to 21st Century grammars such as The Cambridge Grammar of the English Language (Huddleston & Pullum 2002) or Oxford Modern English Grammar (Aarts 2011)-is a locative preposition and can be thought of as standing in for preposition phrases (some people conjecture that where is a 'pro-preposition'). The word which is a pronoun and can be thought of as standing in for noun phrases. Relative clauses are often introduced by wh-words such as which, who or where, or by the relative word that. So in the dog, which they adopted, the phrase the dog is the antecedent, and the phrase which they adopted is the ʀᴇʟᴀᴛɪᴠᴇ ᴄʟᴀᴜsᴇ modifying that noun phrase. The nominal or noun phrase which is being modified always occurs before the relative clause, and is referred to as the ᴀɴᴛᴇᴄᴇᴅᴇɴᴛ. They modify other phrases, in particular noun phrases, which is the kind of case we are considering here. These are special clauses with gaps in them. Note that the strikethough across the words it and there indicate that we cannot actually leave these gaps filled! If the gap can be filled in using the locative preposition there, use the relative word where:

If the gap can be filled in with the pronoun it, use the relative pronoun which.

What is a relative pronoun