I was excited to see the reviewers for this boot talk about how big the calf opening was - I have a lot of trouble getting boots that fit well in the calf. I have had good luck with Born brand boots, but most normal boots are too small on the widest part of my calf, and the one time I got boots sold specifically for larger calves, the boot shafts were way too large. I hoped these would be perfect in the calves, but when they arrived I was unpleasantly surprised to find that they were actually too narrow in the upper calf. I had to take them to a cobbler and get them stretched before wearing them, and they will only fit over tights, not over skinny jeans. I'm hoping they'll stretch out more as I wear them, which the cobbler assured me they will. Other than that issue, I like them a lot. They are a perfect fit (I wear a 9M) and feel very stable and comfortable when I'm walking.

Just so ladies with similar calves can have the specific info:

I believe the boot shaft is specified as 15.6" in circumference. There is no elastic gusset. My calves are 17" at the widest part, and now that the boots are stretched they are about the same.