This paper is concerned with the concepts of regional controllability for the Riemann-Liouville time fractional diffusion systems of order alpha is an element of (0, 1). The characterizations of strategic actuators to achieve regional controllability are investigated when the control inputs emerge in the differential equations as distributed inputs. In the end, an approach to guarantee the regional controllability of the problems under consideration in the considered subregion with minimum energy control is described and successfully tested through two applications. (C) 2016 Elsevier Ltd. All rights reserved.