But we do know where it is, to quite good precision. We know how much or how little dark matter is present in different galaxies, which matches quite well with

But we do know where it is, to quite good precision. We know how much or how little dark matter is present in different galaxies, which matches quite well with the amount of dark matter that must've been present in the early universe to explain some of the anisotropy of the cosmic microwave background.