大(da)(da)同(tong)(tong)古長(chang)(chang)(chang)城(cheng)(cheng)(cheng)是(shi)萬里長(chang)(chang)(chang)城(cheng)(cheng)(cheng)的(de)(de)(de)(de)重要(yao)(yao)組成(cheng)部(bu)(bu)分(fen),主要(yao)(yao)分(fen)布(bu)(bu)于大(da)(da)同(tong)(tong)市的(de)(de)(de)(de)天鎮(zhen)縣(xian)(xian)(xian)、陽(yang)高(gao)(gao)縣(xian)(xian)(xian)、新(xin)榮區(qu)、左(zuo)云縣(xian)(xian)(xian)、渾源縣(xian)(xian)(xian)、靈(ling)丘縣(xian)(xian)(xian)、廣靈(ling)縣(xian)(xian)(xian)7個(ge)縣(xian)(xian)(xian)區(qu)。大(da)(da)同(tong)(tong)的(de)(de)(de)(de)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)歷史所跨朝代較多,現(xian)存(cun)主要(yao)(yao)是(shi)明代長(chang)(chang)(chang)城(cheng)(cheng)(cheng)。大(da)(da)同(tong)(tong)作為(wei)(wei)當時拱衛(wei)(wei)京都的(de)(de)(de)(de)屏障,明長(chang)(chang)(chang)城(cheng)(cheng)(cheng)分(fen)外長(chang)(chang)(chang)城(cheng)(cheng)(cheng)和(he)內(nei)長(chang)(chang)(chang)城(cheng)(cheng)(cheng),如今的(de)(de)(de)(de)大(da)(da)同(tong)(tong)市居于內(nei)外長(chang)(chang)(chang)城(cheng)(cheng)(cheng)之間(jian),南(nan)部(bu)(bu)和(he)北部(bu)(bu)、西(xi)部(bu)(bu)的(de)(de)(de)(de)行政區(qu)劃線大(da)(da)部(bu)(bu)分(fen)以長(chang)(chang)(chang)城(cheng)(cheng)(cheng)為(wei)(wei)界。2009年公(gong)布(bu)(bu)的(de)(de)(de)(de)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)資源調查數據中,大(da)(da)同(tong)(tong)市境內(nei)明代長(chang)(chang)(chang)城(cheng)(cheng)(cheng)343167米(mi),共(gong)有長(chang)(chang)(chang)城(cheng)(cheng)(cheng)烽火臺(tai)、古堡(bao)等(deng)843處(chu)。1986年8月18日,大(da)(da)同(tong)(tong)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)被山西(xi)省人民政府公(gong)布(bu)(bu)為(wei)(wei)第(di)二批省級(ji)文物保護單位。相關(guan)的(de)(de)(de)(de)壁(bi)畫、雕刻(ke)、碑文等(deng)與長(chang)(chang)(chang)城(cheng)(cheng)(cheng)有直接關(guan)系的(de)(de)(de)(de)文物超過2000處(chu)。天鎮(zhen)縣(xian)(xian)(xian)新(xin)平(ping)堡(bao)的(de)(de)(de)(de)玉皇(huang)閣鎮(zhen)邊樓以及修在(zai)海拔1736米(mi)山頂上的(de)(de)(de)(de)樺(hua)門堡(bao),陽(yang)高(gao)(gao)縣(xian)(xian)(xian)墩臺(tai)密布(bu)(bu)的(de)(de)(de)(de)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)鄉,新(xin)榮區(qu)拱衛(wei)(wei)北魏皇(huang)陵(ling)的(de)(de)(de)(de)方山長(chang)(chang)(chang)城(cheng)(cheng)(cheng)和(he)得勝堡(bao)等(deng)邊墻五堡(bao),左(zuo)云摩天嶺兩(liang)個(ge)制(zhi)高(gao)(gao)點之間(jian)的(de)(de)(de)(de)寧魯(lu)樓,靈(ling)丘牛幫口(kou)的(de)(de)(de)(de)內(nei)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)都是(shi)大(da)(da)同(tong)(tong)長(chang)(chang)(chang)城(cheng)(cheng)(cheng)的(de)(de)(de)(de)精美華(hua)章。
據《三云(yun)(yun)籌俎(zu)考·大(da)(da)(da)同(tong)(tong)(tong)(tong)總鎮(zhen)圖(tu)說》統計(ji),大(da)(da)(da)同(tong)(tong)(tong)(tong)鎮(zhen)先后修大(da)(da)(da)邊(bian)(bian)、二(er)邊(bian)(bian)516.3里(li)(li)(li)(li)(li);內(nei)(nei)五(wu)堡(bao)(bao)、外(wai)(wai)(wai)五(wu)堡(bao)(bao)、塞外(wai)(wai)(wai)五(wu)堡(bao)(bao)、云(yun)(yun)岡(gang)六堡(bao)(bao)等主要城(cheng)(cheng)(cheng)(cheng)堡(bao)(bao)72座(zuo)(城(cheng)(cheng)(cheng)(cheng)20,堡(bao)(bao)52);邊(bian)(bian)城(cheng)(cheng)(cheng)(cheng)776個(ge);火路(lu)墩(dun)833個(ge)。在(zai)大(da)(da)(da)同(tong)(tong)(tong)(tong)明長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)自居庸(yong)(yong)關以(yi)西(xi)(xi),分南北(bei)(bei)兩(liang)線到山西(xi)(xi)偏關會合(he),被稱為內(nei)(nei)、外(wai)(wai)(wai)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)。外(wai)(wai)(wai)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)即(ji)居庸(yong)(yong)關西(xi)(xi)北(bei)(bei)經(jing)(jing)赤(chi)城(cheng)(cheng)(cheng)(cheng)、崇禮、張家(jia)口(kou)(kou)、萬全(quan)、懷(huai)安(an)(an)而進(jin)(jin)(jin)入(ru)大(da)(da)(da)同(tong)(tong)(tong)(tong)市(shi)的(de)(de)(de)(de)天(tian)鎮(zhen)、陽(yang)高、大(da)(da)(da)同(tong)(tong)(tong)(tong)、左(zuo)云(yun)(yun)沿(yan)內(nei)(nei)蒙(meng)古、山西(xi)(xi)交界(jie)(jie)(jie)處,達于(yu)偏關、河曲;內(nei)(nei)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)從居庸(yong)(yong)關西(xi)(xi)南經(jing)(jing)河北(bei)(bei)易縣(xian)(xian)、渾源、阜平而進(jin)(jin)(jin)入(ru)大(da)(da)(da)同(tong)(tong)(tong)(tong)市(shi)的(de)(de)(de)(de)靈(ling)(ling)丘、渾源,再經(jing)(jing)應縣(xian)(xian)、繁峙、神池而至老營。據現存長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)實測,外(wai)(wai)(wai)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)分別由懷(huai)安(an)(an)縣(xian)(xian)桃溝村(cun)(cun)、西(xi)(xi)洋(yang)河鄉馬市(shi)口(kou)(kou)南北(bei)(bei)兩(liang)路(lu)進(jin)(jin)(jin)入(ru)天(tian)鎮(zhen)縣(xian)(xian)境,在(zai)新平樂村(cun)(cun)與西(xi)(xi)路(lu)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)相交。天(tian)鎮(zhen)境內(nei)(nei)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)約 105華(hua)(hua)里(li)(li)(li)(li)(li),存黃土夯筑(zhu)的(de)(de)(de)(de)墩(dun)臺(tai)61座(zuo)。由天(tian)鎮(zhen)水磨口(kou)(kou)向(xiang)(xiang)(xiang)西(xi)(xi)三里(li)(li)(li)(li)(li)進(jin)(jin)(jin)入(ru)陽(yang)高縣(xian)(xian)十(shi)九(jiu)墩(dun)村(cun)(cun)界(jie)(jie)(jie),至鎮(zhen)邊(bian)(bian)堡(bao)(bao)西(xi)(xi)出陽(yang)高進(jin)(jin)(jin)入(ru)大(da)(da)(da)同(tong)(tong)(tong)(tong)市(shi)區境。陽(yang)高境內(nei)(nei)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)計(ji) 100余里(li)(li)(li)(li)(li),現存夯土處臺(tai) 119座(zuo)。從陽(yang)高鎮(zhen)邊(bian)(bian)堡(bao)(bao)向(xiang)(xiang)(xiang)西(xi)(xi)約八華(hua)(hua)里(li)(li)(li)(li)(li)進(jin)(jin)(jin)入(ru)大(da)(da)(da)同(tong)(tong)(tong)(tong)元墩(dun)村(cun)(cun)界(jie)(jie)(jie),經(jing)(jing)鎮(zhen)川口(kou)(kou)、宏(hong)賜堡(bao)(bao)、鎮(zhen)羌(qiang)堡(bao)(bao),經(jing)(jing)拒(ju)墻口(kou)(kou)、拒(ju)門口(kou)(kou)、助(zhu)馬口(kou)(kou)至十(shi)三邊(bian)(bian),轉南至磚(zhuan)樓(lou)(lou)溝入(ru)左(zuo)云(yun)(yun)縣(xian)(xian)界(jie)(jie)(jie)。另(ling)一條(tiao)由宏(hong)賜堡(bao)(bao)向(xiang)(xiang)(xiang)西(xi)(xi)經(jing)(jing)新榮、破魯至吳施窯入(ru)左(zuo)云(yun)(yun)界(jie)(jie)(jie),這道(dao)(dao)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)當地人稱“二(er)道(dao)(dao)邊(bian)(bian)”。南北(bei)(bei)兩(liang)道(dao)(dao)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)共 210華(hua)(hua)里(li)(li)(li)(li)(li)。長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)由大(da)(da)(da)同(tong)(tong)(tong)(tong)磚(zhuan)樓(lou)(lou)向(xiang)(xiang)(xiang)南進(jin)(jin)(jin)入(ru)左(zuo)云(yun)(yun)縣(xian)(xian)保安(an)(an)堡(bao)(bao)地界(jie)(jie)(jie),至二(er)十(shi)邊(bian)(bian)向(xiang)(xiang)(xiang)西(xi)(xi)北(bei)(bei)出左(zuo)云(yun)(yun)進(jin)(jin)(jin)入(ru)右玉(yu)縣(xian)(xian)界(jie)(jie)(jie)。長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)在(zai)左(zuo)云(yun)(yun)境內(nei)(nei)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)約86華(hua)(hua)里(li)(li)(li)(li)(li)。以(yi)上這段(duan)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)在(zai)大(da)(da)(da)同(tong)(tong)(tong)(tong)市(shi)境內(nei)(nei)約長(chang)(chang)(chang)(chang)(chang)(chang)(chang) 501華(hua)(hua)里(li)(li)(li)(li)(li)。大(da)(da)(da)同(tong)(tong)(tong)(tong)市(shi)、渾源、靈(ling)(ling)丘縣(xian)(xian)境內(nei)(nei)的(de)(de)(de)(de)明長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)周內(nei)(nei)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)。渾源境內(nei)(nei)計(ji) 160華(hua)(hua)里(li)(li)(li)(li)(li),靈(ling)(ling)丘境內(nei)(nei)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)約 190華(hua)(hua)里(li)(li)(li)(li)(li)。明內(nei)(nei)、外(wai)(wai)(wai)長(chang)(chang)(chang)(chang)(chang)(chang)(chang)城(cheng)(cheng)(cheng)(cheng)在(zai)大(da)(da)(da)同(tong)(tong)(tong)(tong)境內(nei)(nei)總長(chang)(chang)(chang)(chang)(chang)(chang)(chang)為 800多華(hua)(hua)里(li)(li)(li)(li)(li)。為山西(xi)(xi)省重點文物(wu)保護單位。