I don't think US News ranks residency programs. They rank hospitals, so that patients can feel comforted when they go to a mammoth hospital to get their issues taken care of, even though if you're getting your gall bladder out it's probably better to be at a community hospital where they do more of them.
Since a lot of doctors don't even know what pathologists do, a ranking of departments would be useless. We would hear a number of jokes like "so I guess they do great autopsies there!" or maybe even, "what, do they bring some of their autopsy patients back to life?" Ha.
I take pride in the fact that there are no "official" or even semi-official path department rankings. There are only individual opinions, which you must form for yourself. There are a lot of good programs out there, and it would not be very helpful to try to rank any of the top 20-30 programs out there, because each of them probably has something that makes their program unique. I visited a lot of the top programs, some of them I wouldn't want to do residency at. Most of the big academic centers have experts in certain areas, many of them occasionally move around to different places. There are certain places that are more well known than others (and highly regarded) for certain subspecialty areas like GI path, endocrine path, or informatics to name a few areas. That doesn't necessarily mean these places are better for any one person to do residency at.
I object to the whole "ranking" business. My med school UMass is somewhere pretty low on the list of US medical schools, mostly because only massachusetts residents are admitted, thus the "selectivity index" or whatever the crap it is called is not as competitive. BS. I received a great education here, matched at my #1 choice for residency, and will go into residency with a strong grasp of medicine. And my clinical training has been wonderful, and when I have done rotations with med students from other schools I have come away with feeling as though I and my classmates seem to have been prepared better for clinical medicine. I wouldn't have traded my time here for any other med school in the country including all those 80 or whatever are more "highly ranked." It's garbage. Don't let rankings rule your decisions. The problem is that this is often all that people have to go on, and when they hear that a certain program is "top 10" it becomes an important factor because it is hard to distinguish between schools or programs. I have trained under doctors who did their schooling and residencies at the top programs and at unheralded ones, and frankly it mostly depends on the individual, not where they trained.
That being said, there is a bit of a hierarchy in path programs. The bigger, more highly regarded academic institutions have a reputation for putting out great pathologists and academicians, as well as providing more rigorous training. But amongst the top 20-30, there isn't a huge difference. Basically, what ends up happening is that when you go on interviews, most of these programs will tell you how they are the best and their residents get the top jobs, blah blah blah. And then, when people end up picking a program to go to, they will end up probably thinking that their program is "even better I had heard" in regards to path training. That's kind of why not everyone ranks the same program #1. The top candidates end up scattered all over.