I purchased this in my normal shoe size of 11.5D and they fit just right.  Quite often, I need to order a size 12 if the boot has insulation to allow for the extra thickness, but my heels slipped in the size 12 of this boot so I bought the 11.5 instead.  Keen advises that most of their boots run a half size small (maybe even a full size small), so for me the Anchorage is an exception to this.  In those I have tried that do run small, I could use a size 12.5, but that size is not available.

The boots are easy to put on with the double pulls and my narrow heels do not slip while wearing a medium weight sock.  They are also warm and waterproof for winter wear, and I find them to be quite comfortable for my often tender feet.  They would be good for walking the dog in winter if you have this to do.  So I agree with the vast majority of the other reviewers that this is a great boot and can recommend them to others.  With Amazon's return policies you really can't go wrong if they don't work out or you need to exchange sizes.  I bought the black color and have now ordered the brown also.