In the 1817, Wuerttemberg was divided into four kreise (singular, kreis).  The word, "kreis," literally means "circle," but is usually translated into English as "district."  The kreise of Wuerttemberg were further subdivided into oberamter [oberämpter] (singular, oberamt [oberämpt]).  The word, "oberamt," literally means "upper office," but could be loosely translated as "main office" or "headquarters" — oberampter were the smallest divisions of government administration above the village or town.  Like kreis, the word oberamt is usually translated into English as "district," which is one source of the confusion between the two because, in fact, they are not equivalent. 

The four kreise of Wuerttemberg are listed below with their included oberampter.  These were abolished in 1938.

(Names in red-brown are for my own personal convenience as they are the origins of my ancestors.)