Mine are 28.5" ish by 9"....but the quick disconnects add about 1.5-2 inches...so figure 30" ish. And those are ball lock kegs. I don't know if pin lock kegs/disconnects are different.
Mine which are Cornelius Super Champion 5 Gallon kegs From Cornelius of Anoka Minn USA measure 25" high from rubber bottom to rubber top, and 9" Diameter without the Quick Disconnects. With QD attached it is exactly a half inch higher at 25.5"
The pin lock kegs are slightly shorter and larger around than ball locks. The ball locks and ball lock connectors are a bit more common. If you are short on vertical space, the pin locks are the way to go.