It’s really not possible to answer this question, as the “web” isn’t measured in terms of depth.
The term “deep web” is credited to computer scientist Michael K. Bergman in 2001, who used it in the context of search engine indexing. What he was referring to is that, metaphorically, when a search engine is crawling the web looking for content, it’s like a net being dragged across the ocean. In other words, that net won’t catch everything.
Thus, the types of things that would be in the “deep web” might include the contents of your email inbox, anything behind a paywall (like Netflix or YouTube Red), or private social media profiles.
However, I know you meant the dark web. Even so, the dark web isn’t any “deeper” than the “deep web,” because the internet isn’t really like an ocean. The dark web would be content that’s hidden by layers of encryption, on networks called “darknets.”
I actually found an image that was described as a “map” of the internet, which looks like a giant brain:
Source
So, where would the dark web be in all of that? I don’t know for certain, but probably spread out over many different locations. One of the networks that people refer to as the “dark web” is Tor, and it’s made up of many different “nodes” (computers running Tor).
Using the brain analogy again, these nodes would be like synapses in the brain, sending data from one part to another. This is one reason that the “ocean” analogy isn’t very accurate.
Maybe you could think of the dark web as being in one small location of this “internet map,” because only so many computers are running software like Tor, in relation to the rest of the world.
This is about the best answer I can give, because the terms are so vague to begin with.