A vast expanse of territory in northern and eastern parts of occupied France comprising a total of six départements and parts of four others running from the mouth of the Somme to the Swiss frontier in the Jura.[1] This area was separated from the rest of the Occupied Zone by a demarcation line and was effectively cut off from the rest of France.[1] The terms zone réservée ("reserved zone") and zone interdite were often used interchangeably, but some sources distinguish a smaller forbidden zone, comprising parts of Somme, Aisne and Ardennes départements, from the larger reserved zone.[1] This extra demarcation line never seems to have existed beyond theory.[1]