Grimsley is an unincorporated community and census-designated place in Fentress County, Tennessee, United States. Its population was 1,167 as of the 2010 census. Its ZIP code is 38565.The community is located in southern Fentress County on the Cumberland Plateau. The settled part is located on high ground in the center of the CDP, with elevations ranging from 1,700 to 1,800 feet. The west side of the CDP drops into the gorge of the East Fork of the Obey River, with a bottom elevation of 800 to 900 feet, and the east side follows the valley of the North Prong of Clear Fork, with an elevation of 1,600 feet. Both rivers are part of the Cumberland River watershed.U.S. Route 127 is the main road through the community, leading north 12 miles to Jamestown, the Fentress County seat, and south 6.5 miles to Clarkrange. Tennessee State Route 85 forms the southwestern edge of the CDP, dropping by switchbacks into the gorge of the East Fork of the Obey and leading 33 miles to Livingston.