Greenville is located in the northwestern part of the state of South Carolina and a city and seat of Greenville County. It sits in the foothills of the Blu Ridge Mountains and along the Reedy River. The area where the present-day Greenville stands were called Pleasantburg when it was settled in the 1760s and then renamed to Greenville after Isaac Green, who was an early settler in 1831. The area was considered as a summer resort community before the 1860s. It then became the western terminus for the Greenville and Columbia Railroad, and after which, the city has served as the commercial center for Piedmont and for the nearby Appalachian Mountains. The city has vehemently opposed the nullification - a doctrine in the United States history wherein a state, within its territorial jurisdiction, has the right to declare any federal law as null and void that violates its voluntary compact embodied in the Constitution.