Where’s that or where is it?

I just have a quick question regarding the use of ‘that’ and ‘is’. When someone tells you about a place, for instance a dental office, do you say where’s that? Or where is it? to ask about the location.

Some additional comments to @Dan Bron's comment

Either. Both are used frequently. – Dan Bron

I agree that both are used frequently, but if I were to distinguish between the two:

Example of "Where's that?"

"So can you make it to the event at (something something) park?"

"Where's that?"

Example of "Where is it?"

"Are you at the park yet?"

"Not yet. I'm having trouble finding it. Where is it?"

Explanation

"Where is that?" contains a nuance that the person who mentioned the place has a responsibility to explain it more to you:

"Where is that? (I've never heard of it. You should explain it to me so we're on the same page.)"

"That" is more directed that "it", so "that" is used to imply that the place in question is not associated with you (because you don't know about it yet) and that it's more associated with the person you're talking to (because he/she knows about it)

"Where is it?" is used when you and the person you're talking to both know about the place, but you're simply having trouble finding it.

They mean the same but are "pragmatically" different. "Where's that?" refers to what the person mentioned in a sentence. The "that" pronoun refers to the other person's mentioning of a thing in their speech.

WHEREAS:

"Where is it? refers to the object (referent) in the real world the person referred to. These differences are important if one wants to understand this [ahem] in English conversational patterns.