1970年(nian)(nian),懷德縣文(wen)(wen)化部(bu)門對(dui)境內(nei)的(de)遺址(zhi)進行了全面(mian)的(de)普查,在城(cheng)址(zhi)內(nei)采集、征集各類文(wen)(wen)物(wu)數十件。1983、2009年(nian)(nian),通過第(di)二次(ci)、第(di)三次(ci)全國文(wen)(wen)物(wu)普查,對(dui)城(cheng)址(zhi)進行了系統的(de)調查和著(zhu)錄(lu)。
五家子城址周長近3000米,具有州(zhou)(zhou)治規模,可能為遼信州(zhou)(zhou)下轄之州(zhou)(zhou)、縣(xian)城。
城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)址(zhi)分為內(nei)(nei)、外(wai)二(er)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng),城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)垣均夯土構(gou)筑(zhu)。外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)大致呈南(nan)北(bei)(bei)(bei)(bei)向的(de)(de)(de)長方(fang)形(xing)(xing)(xing),東(dong)、西(xi)兩(liang)墻(qiang)(qiang)(qiang)(qiang)長約(yue)(yue)823米,南(nan)、北(bei)(bei)(bei)(bei)兩(liang)墻(qiang)(qiang)(qiang)(qiang)長約(yue)(yue)609.5米,周長約(yue)(yue)2865米。外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)殘(can)損嚴重(zhong),城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)垣基(ji)(ji)本無存(cun)(cun),是(shi)否存(cun)(cun)有(you)馬面(mian)(mian)、甕門(men)等遺跡(ji)(ji)(ji)已不(bu)得而(er)知。外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)四角建有(you)角樓,東(dong)北(bei)(bei)(bei)(bei)角樓現(xian)存(cun)(cun)好,平(ping)面(mian)(mian)近(jin)圓(yuan)(yuan)形(xing)(xing)(xing),直徑(jing)約(yue)(yue)12米,殘(can)高約(yue)(yue)2米,其余(yu)(yu)3處角樓地(di)表(biao)僅見稍高于地(di)表(biao)的(de)(de)(de)殘(can)跡(ji)(ji)(ji)。外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)東(dong)墻(qiang)(qiang)(qiang)(qiang)位置,距內(nei)(nei)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)南(nan)墻(qiang)(qiang)(qiang)(qiang)約(yue)(yue)30米處,現(xian)存(cun)(cun)一高約(yue)(yue)6米的(de)(de)(de)圓(yuan)(yuan)形(xing)(xing)(xing)臺基(ji)(ji),疑為外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)東(dong)墻(qiang)(qiang)(qiang)(qiang)甕門(men)的(de)(de)(de)殘(can)跡(ji)(ji)(ji)。城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)外(wai)10米處,東(dong)、西(xi)、北(bei)(bei)(bei)(bei)三(san)面(mian)(mian)可見護城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)壕(hao)遺跡(ji)(ji)(ji),唯東(dong)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)不(bu)見城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)壕(hao)跡(ji)(ji)(ji)象,內(nei)(nei)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)位于外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)的(de)(de)(de)東(dong)北(bei)(bei)(bei)(bei)角,東(dong)、北(bei)(bei)(bei)(bei)兩(liang)墻(qiang)(qiang)(qiang)(qiang)借用外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)的(de)(de)(de)東(dong)、北(bei)(bei)(bei)(bei)二(er)墻(qiang)(qiang)(qiang)(qiang),另筑(zhu)西(xi)墻(qiang)(qiang)(qiang)(qiang)和南(nan)墻(qiang)(qiang)(qiang)(qiang)而(er)成。內(nei)(nei)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)平(ping)面(mian)(mian)近(jin)正方(fang)形(xing)(xing)(xing),東(dong)、西(xi)兩(liang)墻(qiang)(qiang)(qiang)(qiang)長約(yue)(yue)341米,南(nan)、北(bei)(bei)(bei)(bei)兩(liang)墻(qiang)(qiang)(qiang)(qiang)長約(yue)(yue)320.5米,周長約(yue)(yue)1323米。其中南(nan)墻(qiang)(qiang)(qiang)(qiang)保(bao)存(cun)(cun)好,基(ji)(ji)寬約(yue)(yue)8米,現(xian)高5~6米,其余(yu)(yu)3面(mian)(mian)墻(qiang)(qiang)(qiang)(qiang)體地(di)表(biao)多僅存(cun)(cun)殘(can)跡(ji)(ji)(ji)。內(nei)(nei)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)四角構(gou)筑(zhu)有(you)角樓,東(dong)北(bei)(bei)(bei)(bei)角樓即為外(wai)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)東(dong)北(bei)(bei)(bei)(bei)角樓。現(xian)存(cun)(cun)東(dong)南(nan)、西(xi)南(nan)角樓,尤以(yi)東(dong)南(nan)角樓較為完(wan)整(zheng),平(ping)面(mian)(mian)近(jin)圓(yuan)(yuan)形(xing)(xing)(xing),基(ji)(ji)寬約(yue)(yue)16米,高約(yue)(yue)8米。內(nei)(nei)城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)未見門(men)址(zhi)與甕城(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)(cheng)遺跡(ji)(ji)(ji)。
外城地表遺(yi)物(wu)(wu)豐富,尤以(yi)外城南(nan)側(ce)近(jin)河一帶(dai)遺(yi)物(wu)(wu)更(geng)為豐富。內城遺(yi)物(wu)(wu)則非常零(ling)星,僅見(jian)(jian)少(shao)量(liang)細(xi)泥質灰陶(tao)(tao)片和白瓷(ci)片,以(yi)及青磚和布紋(wen)(wen)瓦殘片。外城遺(yi)物(wu)(wu)以(yi)陶(tao)(tao)、瓷(ci)器(qi)為主(zhu)。陶(tao)(tao)器(qi)以(yi)泥質灰陶(tao)(tao)為主(zhu),均(jun)輪(lun)制,火候較高、陶(tao)(tao)質堅(jian)硬(ying)。器(qi)形包括罐(guan)、甕、盆、壺等(deng)。陶(tao)(tao)器(qi)紋(wen)(wen)飾多(duo)樣(yang),以(yi)多(duo)種形式的附(fu)加堆紋(wen)(wen)為主(zhu),還可見(jian)(jian)篦齒紋(wen)(wen)、卷云(yun)紋(wen)(wen)等(deng)。另(ling)有(you)少(shao)量(liang)的夾砂陶(tao)(tao),主(zhu)要出(chu)于城外南(nan)側(ce),器(qi)形多(duo)較小,可能為青銅時代遺(yi)物(wu)(wu)。城內出(chu)土瓷(ci)器(qi)均(jun)為白瓷(ci),胎質粗糙,釉(you)色(se)泛(fan)黃,器(qi)形有(you)碗、盤、碟等(deng)。
城(cheng)址雖未發(fa)掘,城(cheng)址的年代、性(xing)質(zhi)認定(ding)尚無充分證(zheng)據,但城(cheng)內出土(tu)遺物的特(te)點表面,遺物多為遼金時期。《遼史》信(xin)州(zhou)(zhou)條下(xia)(xia)記(ji)錄信(xin)州(zhou)(zhou)轄三(san)州(zhou)(zhou)、二縣。五家(jia)子城(cheng)址周(zhou)長近3000米,具有州(zhou)(zhou)治規(gui)模,可(ke)能(neng)為遼信(xin)州(zhou)(zhou)下(xia)(xia)轄之州(zhou)(zhou)、縣城(cheng)。對研究當時的政治、經濟、軍事(shi)、文化、交(jiao)通等各方面都具有較高的歷史價值。