The definition of basic territorial units is a standard, although a rather important step in any spatial analysis of social and economic change. It becomes usually a problem when a comparative approach is taken. Therefore, in this paper I shall start with a brief presentation of: (a) the administrative structure of Poland and its evolution over recent decades; (b) the nature of administrative units and their relation to the structure of social and economic space; and (c) the availability of statistical data, including time series of such data, for each type of units
