大(da)(da)同(tong)古長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)是(shi)萬里長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)的(de)(de)(de)(de)重要(yao)組成部分,主要(yao)分布(bu)(bu)于(yu)大(da)(da)同(tong)市的(de)(de)(de)(de)天鎮(zhen)縣(xian)(xian)、陽高縣(xian)(xian)、新榮(rong)區(qu)、左(zuo)云縣(xian)(xian)、渾源縣(xian)(xian)、靈丘縣(xian)(xian)、廣靈縣(xian)(xian)7個(ge)縣(xian)(xian)區(qu)。大(da)(da)同(tong)的(de)(de)(de)(de)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)歷史所跨朝(chao)代(dai)(dai)較多,現存主要(yao)是(shi)明(ming)代(dai)(dai)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)。大(da)(da)同(tong)作(zuo)為當時拱衛(wei)京都(dou)的(de)(de)(de)(de)屏障,明(ming)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)分外長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)和(he)內長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng),如(ru)今的(de)(de)(de)(de)大(da)(da)同(tong)市居于(yu)內外長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)之間,南部和(he)北部、西部的(de)(de)(de)(de)行(xing)政區(qu)劃線大(da)(da)部分以長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)為界。2009年公布(bu)(bu)的(de)(de)(de)(de)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)資源調查數據中,大(da)(da)同(tong)市境(jing)內明(ming)代(dai)(dai)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)343167米(mi),共有(you)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)烽火臺(tai)、古堡(bao)(bao)等843處(chu)。1986年8月18日,大(da)(da)同(tong)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)被山西省(sheng)人民(min)政府公布(bu)(bu)為第二批省(sheng)級文物保護單(dan)位(wei)。相關(guan)的(de)(de)(de)(de)壁(bi)畫、雕刻、碑(bei)文等與長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)有(you)直接關(guan)系的(de)(de)(de)(de)文物超過(guo)2000處(chu)。天鎮(zhen)縣(xian)(xian)新平堡(bao)(bao)的(de)(de)(de)(de)玉皇閣(ge)鎮(zhen)邊樓(lou)以及修(xiu)在海(hai)拔1736米(mi)山頂上的(de)(de)(de)(de)樺(hua)門堡(bao)(bao),陽高縣(xian)(xian)墩臺(tai)密布(bu)(bu)的(de)(de)(de)(de)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)鄉,新榮(rong)區(qu)拱衛(wei)北魏皇陵的(de)(de)(de)(de)方(fang)山長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)和(he)得(de)勝堡(bao)(bao)等邊墻五堡(bao)(bao),左(zuo)云摩(mo)天嶺兩個(ge)制高點(dian)之間的(de)(de)(de)(de)寧(ning)魯樓(lou),靈丘牛(niu)幫(bang)口的(de)(de)(de)(de)內長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)都(dou)是(shi)大(da)(da)同(tong)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)的(de)(de)(de)(de)精美華章。
據《三(san)云(yun)(yun)籌俎(zu)考·大(da)(da)(da)同(tong)(tong)總鎮(zhen)圖說(shuo)》統計(ji)(ji),大(da)(da)(da)同(tong)(tong)鎮(zhen)先(xian)后修大(da)(da)(da)邊(bian)、二邊(bian)516.3里(li)(li)(li)(li)(li);內(nei)(nei)五(wu)堡(bao)、外(wai)(wai)五(wu)堡(bao)、塞外(wai)(wai)五(wu)堡(bao)、云(yun)(yun)岡六堡(bao)等主(zhu)要城(cheng)(cheng)(cheng)(cheng)(cheng)堡(bao)72座(城(cheng)(cheng)(cheng)(cheng)(cheng)20,堡(bao)52);邊(bian)城(cheng)(cheng)(cheng)(cheng)(cheng)776個;火路(lu)(lu)墩(dun)833個。在(zai)大(da)(da)(da)同(tong)(tong)明長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)自(zi)居(ju)(ju)庸(yong)關(guan)以西(xi)(xi),分南(nan)(nan)北(bei)兩線到山(shan)西(xi)(xi)偏關(guan)會合(he),被稱為內(nei)(nei)、外(wai)(wai)長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)。外(wai)(wai)長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)即居(ju)(ju)庸(yong)關(guan)西(xi)(xi)北(bei)經赤城(cheng)(cheng)(cheng)(cheng)(cheng)、崇(chong)禮、張家口(kou)(kou)(kou)、萬全、懷安(an)而(er)(er)進(jin)入(ru)(ru)大(da)(da)(da)同(tong)(tong)市(shi)(shi)的天(tian)鎮(zhen)、陽(yang)(yang)(yang)高(gao)、大(da)(da)(da)同(tong)(tong)、左(zuo)(zuo)(zuo)云(yun)(yun)沿(yan)內(nei)(nei)蒙古、山(shan)西(xi)(xi)交(jiao)界(jie)(jie)處,達(da)于偏關(guan)、河(he)(he)曲;內(nei)(nei)長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)從居(ju)(ju)庸(yong)關(guan)西(xi)(xi)南(nan)(nan)經河(he)(he)北(bei)易縣(xian)(xian)、渾(hun)源、阜平而(er)(er)進(jin)入(ru)(ru)大(da)(da)(da)同(tong)(tong)市(shi)(shi)的靈(ling)(ling)丘(qiu)、渾(hun)源,再經應縣(xian)(xian)、繁(fan)峙、神池而(er)(er)至(zhi)(zhi)老營。據現存(cun)長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)實測,外(wai)(wai)長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)分別由(you)懷安(an)縣(xian)(xian)桃(tao)溝村(cun)(cun)(cun)、西(xi)(xi)洋河(he)(he)鄉(xiang)馬市(shi)(shi)口(kou)(kou)(kou)南(nan)(nan)北(bei)兩路(lu)(lu)進(jin)入(ru)(ru)天(tian)鎮(zhen)縣(xian)(xian)境(jing),在(zai)新平樂(le)村(cun)(cun)(cun)與西(xi)(xi)路(lu)(lu)長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)相交(jiao)。天(tian)鎮(zhen)境(jing)內(nei)(nei)長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)約 105華(hua)(hua)里(li)(li)(li)(li)(li),存(cun)黃土(tu)夯(hang)筑的墩(dun)臺(tai)(tai)61座。由(you)天(tian)鎮(zhen)水磨口(kou)(kou)(kou)向(xiang)(xiang)(xiang)西(xi)(xi)三(san)里(li)(li)(li)(li)(li)進(jin)入(ru)(ru)陽(yang)(yang)(yang)高(gao)縣(xian)(xian)十(shi)(shi)九墩(dun)村(cun)(cun)(cun)界(jie)(jie),至(zhi)(zhi)鎮(zhen)邊(bian)堡(bao)西(xi)(xi)出陽(yang)(yang)(yang)高(gao)進(jin)入(ru)(ru)大(da)(da)(da)同(tong)(tong)市(shi)(shi)區境(jing)。陽(yang)(yang)(yang)高(gao)境(jing)內(nei)(nei)長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)計(ji)(ji) 100余里(li)(li)(li)(li)(li),現存(cun)夯(hang)土(tu)處臺(tai)(tai) 119座。從陽(yang)(yang)(yang)高(gao)鎮(zhen)邊(bian)堡(bao)向(xiang)(xiang)(xiang)西(xi)(xi)約八(ba)華(hua)(hua)里(li)(li)(li)(li)(li)進(jin)入(ru)(ru)大(da)(da)(da)同(tong)(tong)元墩(dun)村(cun)(cun)(cun)界(jie)(jie),經鎮(zhen)川口(kou)(kou)(kou)、宏(hong)賜(si)堡(bao)、鎮(zhen)羌堡(bao),經拒墻口(kou)(kou)(kou)、拒門口(kou)(kou)(kou)、助馬口(kou)(kou)(kou)至(zhi)(zhi)十(shi)(shi)三(san)邊(bian),轉南(nan)(nan)至(zhi)(zhi)磚樓溝入(ru)(ru)左(zuo)(zuo)(zuo)云(yun)(yun)縣(xian)(xian)界(jie)(jie)。另一條由(you)宏(hong)賜(si)堡(bao)向(xiang)(xiang)(xiang)西(xi)(xi)經新榮、破魯至(zhi)(zhi)吳(wu)施窯(yao)入(ru)(ru)左(zuo)(zuo)(zuo)云(yun)(yun)界(jie)(jie),這道(dao)長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)當(dang)地人稱“二道(dao)邊(bian)”。南(nan)(nan)北(bei)兩道(dao)長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)共 210華(hua)(hua)里(li)(li)(li)(li)(li)。長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)由(you)大(da)(da)(da)同(tong)(tong)磚樓向(xiang)(xiang)(xiang)南(nan)(nan)進(jin)入(ru)(ru)左(zuo)(zuo)(zuo)云(yun)(yun)縣(xian)(xian)保安(an)堡(bao)地界(jie)(jie),至(zhi)(zhi)二十(shi)(shi)邊(bian)向(xiang)(xiang)(xiang)西(xi)(xi)北(bei)出左(zuo)(zuo)(zuo)云(yun)(yun)進(jin)入(ru)(ru)右玉縣(xian)(xian)界(jie)(jie)。長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)在(zai)左(zuo)(zuo)(zuo)云(yun)(yun)境(jing)內(nei)(nei)長(chang)(chang)(chang)(chang)(chang)約86華(hua)(hua)里(li)(li)(li)(li)(li)。以上這段長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)在(zai)大(da)(da)(da)同(tong)(tong)市(shi)(shi)境(jing)內(nei)(nei)約長(chang)(chang)(chang)(chang)(chang) 501華(hua)(hua)里(li)(li)(li)(li)(li)。大(da)(da)(da)同(tong)(tong)市(shi)(shi)、渾(hun)源、靈(ling)(ling)丘(qiu)縣(xian)(xian)境(jing)內(nei)(nei)的明長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)周內(nei)(nei)長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)。渾(hun)源境(jing)內(nei)(nei)計(ji)(ji) 160華(hua)(hua)里(li)(li)(li)(li)(li),靈(ling)(ling)丘(qiu)境(jing)內(nei)(nei)長(chang)(chang)(chang)(chang)(chang)約 190華(hua)(hua)里(li)(li)(li)(li)(li)。明內(nei)(nei)、外(wai)(wai)長(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)(cheng)在(zai)大(da)(da)(da)同(tong)(tong)境(jing)內(nei)(nei)總長(chang)(chang)(chang)(chang)(chang)為 800多華(hua)(hua)里(li)(li)(li)(li)(li)。為山(shan)西(xi)(xi)省重點文物保護(hu)單位(wei)。