ROCROY, an arrondissement of France, in the department of the Ardennes, which extends over 295 square miles. It comprehends five cantons and sixty-eight communes, and the population in 1836 amounted to 46,156. The capital is a fortified city of the same name, situated in the midst of a wood. It contains 600 houses, and in 1836 had 3682 inhabitants. It is celebrated for its siege in 1643, when taken from the Spaniards by the great Condé. Long. 4. 26. 32. E. Lat. 49. 55. 36. N.