How big do Box turtles get in Kansas?

The only box turtles indigenous to Kansas are the Ornate box turtle and the Three toed Box turtle. They both grow to an adult shell length of 6 inches. The biggest box turtles are Gulf Coast box turtles (not in Kansas) and they can grow to 8 inches or more in length.

To answer your question, the state they are in has no affect on how big they grow so if you put a gulf coast box turtle in Kansas it can still grow to 8 inches or more.:-)