1970年,懷德縣文(wen)(wen)化部門對境內(nei)(nei)的(de)遺址(zhi)進(jin)行了(le)全(quan)面的(de)普(pu)查,在城(cheng)址(zhi)內(nei)(nei)采集、征集各類文(wen)(wen)物數(shu)十件。1983、2009年,通(tong)過第二次(ci)、第三次(ci)全(quan)國(guo)文(wen)(wen)物普(pu)查,對城(cheng)址(zhi)進(jin)行了(le)系統(tong)的(de)調(diao)查和著(zhu)錄(lu)。
五家子城址周長近(jin)3000米(mi),具有州(zhou)治規模,可能(neng)為(wei)遼(liao)信州(zhou)下(xia)轄之州(zhou)、縣城。
城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)址分為內(nei)(nei)(nei)(nei)、外(wai)二城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng),城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)垣(yuan)均夯土構(gou)筑(zhu)(zhu)。外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)大(da)致呈南(nan)(nan)(nan)(nan)北向的長(chang)(chang)(chang)方形,東(dong)(dong)(dong)、西(xi)(xi)(xi)兩(liang)(liang)墻(qiang)(qiang)(qiang)長(chang)(chang)(chang)約(yue)(yue)(yue)823米(mi)(mi)(mi),南(nan)(nan)(nan)(nan)、北兩(liang)(liang)墻(qiang)(qiang)(qiang)長(chang)(chang)(chang)約(yue)(yue)(yue)609.5米(mi)(mi)(mi),周(zhou)長(chang)(chang)(chang)約(yue)(yue)(yue)2865米(mi)(mi)(mi)。外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)殘(can)損嚴(yan)重,城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)垣(yuan)基(ji)本無(wu)存(cun),是否存(cun)有馬面(mian)、甕(weng)門(men)等遺跡(ji)已(yi)不得而(er)知。外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)四(si)角(jiao)(jiao)建有角(jiao)(jiao)樓(lou),東(dong)(dong)(dong)北角(jiao)(jiao)樓(lou)現(xian)存(cun)好,平面(mian)近圓(yuan)形,直徑約(yue)(yue)(yue)12米(mi)(mi)(mi),殘(can)高(gao)約(yue)(yue)(yue)2米(mi)(mi)(mi),其余3處角(jiao)(jiao)樓(lou)地(di)表(biao)僅(jin)見(jian)(jian)稍高(gao)于(yu)地(di)表(biao)的殘(can)跡(ji)。外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)東(dong)(dong)(dong)墻(qiang)(qiang)(qiang)位置,距內(nei)(nei)(nei)(nei)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)南(nan)(nan)(nan)(nan)墻(qiang)(qiang)(qiang)約(yue)(yue)(yue)30米(mi)(mi)(mi)處,現(xian)存(cun)一高(gao)約(yue)(yue)(yue)6米(mi)(mi)(mi)的圓(yuan)形臺(tai)基(ji),疑為外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)東(dong)(dong)(dong)墻(qiang)(qiang)(qiang)甕(weng)門(men)的殘(can)跡(ji)。城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)外(wai)10米(mi)(mi)(mi)處,東(dong)(dong)(dong)、西(xi)(xi)(xi)、北三面(mian)可(ke)見(jian)(jian)護城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)壕遺跡(ji),唯東(dong)(dong)(dong)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)不見(jian)(jian)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)壕跡(ji)象,內(nei)(nei)(nei)(nei)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)位于(yu)外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)的東(dong)(dong)(dong)北角(jiao)(jiao),東(dong)(dong)(dong)、北兩(liang)(liang)墻(qiang)(qiang)(qiang)借用外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)的東(dong)(dong)(dong)、北二墻(qiang)(qiang)(qiang),另筑(zhu)(zhu)西(xi)(xi)(xi)墻(qiang)(qiang)(qiang)和南(nan)(nan)(nan)(nan)墻(qiang)(qiang)(qiang)而(er)成。內(nei)(nei)(nei)(nei)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)平面(mian)近正方形,東(dong)(dong)(dong)、西(xi)(xi)(xi)兩(liang)(liang)墻(qiang)(qiang)(qiang)長(chang)(chang)(chang)約(yue)(yue)(yue)341米(mi)(mi)(mi),南(nan)(nan)(nan)(nan)、北兩(liang)(liang)墻(qiang)(qiang)(qiang)長(chang)(chang)(chang)約(yue)(yue)(yue)320.5米(mi)(mi)(mi),周(zhou)長(chang)(chang)(chang)約(yue)(yue)(yue)1323米(mi)(mi)(mi)。其中(zhong)南(nan)(nan)(nan)(nan)墻(qiang)(qiang)(qiang)保存(cun)好,基(ji)寬(kuan)約(yue)(yue)(yue)8米(mi)(mi)(mi),現(xian)高(gao)5~6米(mi)(mi)(mi),其余3面(mian)墻(qiang)(qiang)(qiang)體地(di)表(biao)多僅(jin)存(cun)殘(can)跡(ji)。內(nei)(nei)(nei)(nei)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)四(si)角(jiao)(jiao)構(gou)筑(zhu)(zhu)有角(jiao)(jiao)樓(lou),東(dong)(dong)(dong)北角(jiao)(jiao)樓(lou)即為外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)東(dong)(dong)(dong)北角(jiao)(jiao)樓(lou)。現(xian)存(cun)東(dong)(dong)(dong)南(nan)(nan)(nan)(nan)、西(xi)(xi)(xi)南(nan)(nan)(nan)(nan)角(jiao)(jiao)樓(lou),尤以(yi)東(dong)(dong)(dong)南(nan)(nan)(nan)(nan)角(jiao)(jiao)樓(lou)較為完整,平面(mian)近圓(yuan)形,基(ji)寬(kuan)約(yue)(yue)(yue)16米(mi)(mi)(mi),高(gao)約(yue)(yue)(yue)8米(mi)(mi)(mi)。內(nei)(nei)(nei)(nei)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)未見(jian)(jian)門(men)址與(yu)甕(weng)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)遺跡(ji)。
外(wai)城地表遺(yi)(yi)物(wu)豐富(fu),尤以(yi)外(wai)城南側(ce)近河一帶(dai)遺(yi)(yi)物(wu)更(geng)為(wei)豐富(fu)。內城遺(yi)(yi)物(wu)則(ze)非常零星(xing),僅見(jian)少(shao)量細泥質(zhi)灰陶(tao)片和白瓷片,以(yi)及(ji)青磚和布紋(wen)瓦殘(can)片。外(wai)城遺(yi)(yi)物(wu)以(yi)陶(tao)、瓷器(qi)(qi)為(wei)主(zhu)。陶(tao)器(qi)(qi)以(yi)泥質(zhi)灰陶(tao)為(wei)主(zhu),均(jun)(jun)輪制(zhi),火候(hou)較高、陶(tao)質(zhi)堅(jian)硬(ying)。器(qi)(qi)形包括罐、甕、盆、壺等(deng)。陶(tao)器(qi)(qi)紋(wen)飾多(duo)樣,以(yi)多(duo)種形式的附加(jia)堆紋(wen)為(wei)主(zhu),還可見(jian)篦齒紋(wen)、卷云紋(wen)等(deng)。另(ling)有少(shao)量的夾砂陶(tao),主(zhu)要出于城外(wai)南側(ce),器(qi)(qi)形多(duo)較小,可能為(wei)青銅(tong)時代遺(yi)(yi)物(wu)。城內出土(tu)瓷器(qi)(qi)均(jun)(jun)為(wei)白瓷,胎質(zhi)粗(cu)糙(cao),釉色泛黃,器(qi)(qi)形有碗(wan)、盤、碟等(deng)。
城(cheng)(cheng)(cheng)址(zhi)雖(sui)未(wei)發掘,城(cheng)(cheng)(cheng)址(zhi)的(de)(de)年代、性質認(ren)定尚(shang)無充分證據,但城(cheng)(cheng)(cheng)內出土(tu)遺(yi)物的(de)(de)特點表面(mian),遺(yi)物多為遼金時期。《遼史(shi)》信州條下記錄信州轄(xia)三州、二縣。五家(jia)子城(cheng)(cheng)(cheng)址(zhi)周長近3000米,具有(you)州治規(gui)模(mo),可能為遼信州下轄(xia)之州、縣城(cheng)(cheng)(cheng)。對研究當時的(de)(de)政(zheng)治、經濟(ji)、軍事、文(wen)化、交通(tong)等各方面(mian)都具有(you)較(jiao)高的(de)(de)歷(li)史(shi)價值(zhi)。