The article analyzes various approaches to the definition of the concept of «region». The authors give the definition of the regional economic interest. We substantiate the consideration of the territorial individuality as a basis for the formation of mega-enterprise regions. The structure of territorial individuality as a general set of characteristics distinguishing one territory from another is proposed. The authors investigate the tangible assets of the territory as well as the intangible ones. We consider the new forms of the development of the regions – mega-enterprises – in the form of industrial districts and clusters.