Kentrosaurus was not as large a Stegosaurus. In fact it was barely 1 ton, and 15 ft. However, some estimates are 18 ft, and even 13 ft. Unlike Stegosaurus which had 4 spikes on the end of it's tail, it had spikes halfway. It also has 2 spikes going through the body.
Kentrosaurus is only known in Tanzania, although a similar stegosaur is known in Malawi. Although, it has been reported in the USA, it was reclassified as Alcovasaurus.