1780, probably from cord + obsolete 17c. duroy, name of a coarse fabric made in England, of unknown origin. Folk etymology is from *corde du roi "the king's cord," but this is not attested in French, where the term for the cloth was velours à côtes. Applied in U.S. to a road of logs across swampy ground (1780s) on similarity of appearance.
CORDUROY ROAD. A road or causeway constructed with logs laid together over swamps or marshy places. When properly finished earth is thrown between them by which the road is made smooth; but in newly settled parts of the United States they are often left uncovered, and hence are extremely rough and bad to pass over with a carriage. Sometimes they extend many miles. They derive their name from their resemblance to a species of ribbed velvet, called corduroy. [Bartlett]