A numerical study of hydraulic fracture growth from a circular borehole under plane strain conditions is presented. The coupling of fluid flow and rock deformation plays a key role in the fracture reorientation process and in determining the curved fracture path formed. The fracture path is given as a function of both the nondimensional parameter β, which has been previously described in the literature and applies to fracture growth that is dominated by rock fracture toughness, and the recently derived nondimensional parameter χF, which applies to fracture growth that is dominated by fluid viscous dissipation. The results show that the values of β and χF determine the fracture trajectory as the fracture grows from the wellbore and eventually reorients parallel to the maximum far-field stress direction. Thus, for viscous dominated conditions that are typical of field application of hydraulic fracturing for stimulation, χF is a measure of the development of nearwellbore fracture tortuosity. A larger value of χF implies a stronger curvature and fracture tortuosity. The value of χF is reduced by increasing the viscosity and injection rate of the fluid.