Recorded as Darci, Darco, and in England apparently Darko, this is a French surname, or at least a surname of French origins. It is locational from the town of Arcy, and hence the fused form of D'arci or later Darcy, in the departement of La Manche, in Northern France. It is also recorded in the famous English historical record and register of lands, the Domesday Book, in 1086, with that of Norman de Arci of Lincoln. Locational surnames, wherever they are found in the world, are usually 'from' names. That is to say names that were given to people after they left their original homes to move somewhere else, and were best identified by being called after their former homestead, wherever that might be. Over the centuries spelling being at best erratic, and local accents and dialects very thick, often lead to the development of 'sounds like' spellings. In this case the surviving church registers of France, most were destroyed in the famous Revolution of 1792, includes examples such as Jean Darco and his wife Jeanne, nee Barre, at Vendresse, in the Ardennes, on May 26th 1718, and Anne Darcy who married Simon Aubert, on January 25th 1780 at Colombey-les-Belles, Meurther-et-Moselle. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.