Cimarron Redoubt The Cimarron Redoubt ( also known as the Deep Hole Redoubt ) was an improvised U . S . Army fortification south of the city of Ashland in Clark County , Kansas , United States . Built in 1870 near a major trade route ' s crossing of the Cimarron River , it was later used for a variety of civilian purposes , including a post office . Today , it lies abandoned amid farm fields in southern Center Township . History . Southwestern Kansas was the location of some of the fighting of the Comanche War , fought between 1867 and 1875 . In order to protect traffic on the Fort Supply / Fort Dodge trail , U . S . Army soldiers built two redoubt s north and south of the Cimarron River . The southern redoubt , constructed of sandbag s , was erected on the eastern side of Clark Creek south of its confluence with the Cimarron , while the earthen northern redoubt was built along the eastern side of Bear Creek . Named for the streams along which they lie , the two sites are located approximately fourteen miles apart : the Cimarron Redoubt lies nine miles south of Ashland , while the Bear Creek Redoubt lies five miles to the north of the city . Although fighting concluded in the immediate vicinity of the redoubt by 1875 , it and the Bear Creek redoubt remained necessary fortifications in the Army ' s strategy of keeping hostile Native Americans away from settled areas . By the late 1870s , the region was sufficiently peaceful to render the Cimarron Redoubt unnecessary , and it was left to use by local civilians . The next few years saw it converted into a store , and by 1881 , it was the location of the Deep Hole post office . After an undetermined period of time , it was abandoned . Since that time , the redoubt has been remarkably well preserved : the tall grass that now covers it has significantly reduced the rate of erosion . Located in the middle of a field now used for the storage of hay , the grass - covered redoubt is Kansas ' only known sandbag fort . In 1978 , the Cimarron Redoubt ' s excellent state of preservation led to its being placed on the National Register of Historic Places , both for its historical role in military affairs and for the potential archeological value of excavation . The areas recognized as significant include both the fortification and some surrounding fields . Moreover , the National Park Service has recognized the redoubt as one of the principal sites in the valley of the Cimarron River . Structure . Built by soldiers under the command of Captain John Page , the redoubt was constructed in the shape of a square , sixty feet on each side . According to an account by Frances Roe , a later commander ' s wife who was stationed there in January 1873 , it was laid out with many aspects of larger fortification s , such as bastion s , ditches , and a ten - foot - tall parapet . Inside , the fortification included log - reinforced rooms for the garrison that , under Roe ' s supervision , were capable of becoming " clean and cheerful " for a military wife . Today , the walls have been eroded somewhat , especially along Clark Creek on the redoubt ' s southern side ; they are generally only about two or three feet above the surrounding terrain . Nevertheless , its structure is overall strong enough that the redoubt is expected to survive essentially intact long into the future .