They are fairly high, I find them higher than some of the other boots that combine riding/general wear. I have long legs and these come up high enough to not interfere with the saddle flap on both a dressage and a jumping saddle. They don’t come up as high as a regular riding boot, I’d guess about an inch and a half or so below the front of my knee (size 9M). My (colorful) knee-high smartwool socks are generally not visible.
These are pretty handy boots, I can wear warm socks and put orthotics in and do quite a bit of walking and they are comfortable (and yet easy to ride in). They definitely look casual but are great for the wet winters here.
