Thalamotomy and deep brain stimulation (DBS) are important surgical options for patients with tremor-dominant movement disorders. They have provided significant improvements to those with Parkinson’s disease (PD), essential tremor (ET), and dystonic tremor (DT) in their daily quality of life. Both neurosurgery techniques require presurgical imaging to localize targets for electrode placement. The thalamus is a common target for patients with uncontrollable tremor. It is made up of multiple, irregularly shaped nuclei with vague and almost indistinguishable topographies. Improving the localization of these nuclei prior to electrode implantation can potentially reduce surgery times and increase success rates. The use of magnetic resonance imaging (MRI) allows us to study soft tissue structures, such as the brain, noninvasively, with high resolution, and without using ionizing radiation. More recently, the functional activity and connections within the brain can be visualized using MRI sequences that detect signals highly correlated with neuronal activity, a technique called functional MRI (fMRI). In this thesis we aimed to localize specific thalamic nuclei using fMRI, by looking at task-based activations (TB-fMRI) and functional connections in the resting state (RS-fMRI), between the thalamus and the sensory and motor cortices in ET and tremor-dominant PD patients, as well as in healthy controls. Results showed that TB-fMRI and RS-fMRI each localized the motor regions of the thalamus to >10mm from expected motor thalamus locations obtained from surgical lesion locations and literature reported locations. There were no differences in localized motor thalamus locations between groups using either fMRI technique. However, the motor thalamus was more distinctly separated from the sensory thalamus using TB-fMRI. This may ultimately result in a more accurate thalamic mapping process prior to thalamic lesioning or DBS electrode implantation, shorten resulting surgical times and improve overall surgical outcome.