I'm a size 10 for most brands.  I ordered a 10 and they were too big to pretend I could work it out.  I went to a shoe store in Manhattan and tried on the size 9 High Riders and they fit perfectly. The back of the size 9 boot did slightly bang into to my achilles, so not sure if it is discomfort which will eventually become unbearable; therefore, still debating if I should re-order them. I must also mention that while at the shoe store I tried on the Bogs High Classic Boot in a size 9 and it was too small for consideration, so the Bogs High Rider Boots are not true to size, it runs big.