How do I answer 这是哪儿? I'm confused about answering 这是哪儿. Should I answer directly and say that this is a restaurant, or if I should give a general answer and say this is Utica, if someone asks me that question？
It really should depend on the context. Note that "Where am I?" has similar ambiguity in English.

For instance, if I'm at a shop and speaking to someone on the phone who wants to know where I am, and I ask the shopkeeper 这是哪里？, it's expected for the name of the shop (or its location) to be given. This might also hold if I am on the street.

Comparatively, in some cases, I might want less specific information. If someone is bringing me into an unfamiliar store, I might instead expect the answer to indicate what type of store I am in. If I have been driving long distances and have just stopped, I might expect 这是哪里？ (if asked by a passenger I am carrying) to be about what town I am in, not what road I am on.