An urban system is defined as a network of towns, cities and its hinterland characterized by exchange and interdependence. These cities and towns are arranged in a hierarchical settlement pattern within the development continuum in which people, goods, services and capital flow in the city system hierarchy. A national urban system comprises regional urban systems (RUSs) which is dominated by a large urban area. The Indian RUS can be delineated into four broad macro-regional urban systems: Delhi, Kolkata, Chennai, and Mumbai. Given this background this chapter addresses three questions: (1) What are the broad trends of RUSs research in India? (2) What insights have the various conceptual approaches provided to the understanding of Indian regional urbanization? (3) Is there a new approach that can manifest an alternative insight to Indian RUS? Four observations can be made: (1) Indian cities have grown rapidly followed by polarization reversal, (2) hierarchic studies have sparked an interest in regional service development planning utilizing location-allocation models (3) Indian urbanization is characterized by a lack of national primacy but the presence of state primacy and regional rank-size tendency, and (4) complexity approach is a novel approach to model macro-behavior such as city development or urban sprawl using micro-motives or local interaction such as land use changes.