5 ft x 5 ft 5 1/2 in from floor to rail with a 5 and 1/2 in overhang to keep mama from smothering the babies. I always use these on my tile floor when I had a litter and put old carpeting in the bottom. These work great for your 60-70 lb dogs, probably bigger. As long as mom can't slide under the ledge thats the whole point.