Goal-directed movements are associated with unique neurophysiological alterations in motor-related brain regions. This study systematically examined the interhemispheric connectivity between the premotor (dorsal, PMd; ventral, PMv) and the primary motor (M1) cortices using dual-site transcranial magnetic stimulation. We had 30 right-handed young adults (15F; 26.5±4.3yrs) participate in three experimental conditions to examine interhemispheric inhibition (IHI) between: (1) PMd to M1, (2) PMv to M1 and (3) M1 to M1. PMd and PMv were located relative to M1 (PMd: 2cm anterior, 1cm medial; PMv: 3cm anterior, 2.5cm lateral), using each participant’s TS-weighted structural MRI. A 3x3 grid (9 locations with 1cm spacing) was generated for each cortical region (i.e., PMd, PMv, M1) over the right hemisphere. To investigate IHI between these cortical regions, conditioning stimuli were applied to each 9 sub-locations placed over the right PMd, PMv, and M1. The test stimulus over left M1 then occurred after a 10ms interval. Additional trials with only the test stimuli over the left M1 were collected in a pseudorandom manner. IHI ratio was calculated by comparing the mean peak-to-peak motor evoked potential amplitudes of the conditioned to unconditioned trials at each sub-location. The most significant inhibition was found at the center for M1, 1cm anterior and 1cm medial to M1 for PMd, and 2cm anterior and 1.5cm lateral to M1 for PMv. We located the MNI coordinates of these cortical regions for each participant, computing a mean cortical coordinate map. Our results demonstrate the unique contributions of motor-related areas influencing movement.