Formal microfinance organizations have difficulty extending their services to remote rural areas in Kenya, as elsewhere in Africa. This article proposes to map the frontiers of microfinance in Kenya based on poverty incidence and population density. It then presents a spectrum of centralized and decentralized models, from banks to MFIs, SACCOs, ASCAs and ROSCAs. The more decentralized models, which involve greater user-ownership and management, have the potential to provide services to poorer people and in rural areas due to inherently lower cost structures and key characteristics of their services, despite many challenges to their long-term effectiveness and sustainability. Five organizations in Kenya that are reaching into rural areas are analysed to explore where the frontiers lie. It concludes by discussing potential strategies for the improvement of decentralized services as the 'bottom up' spike of a two-pronged approach which complements centralized service delivery.