1970年,懷德縣文化部門對(dui)境內(nei)的(de)遺(yi)址進行(xing)了(le)全面的(de)普查(cha),在城址內(nei)采集、征集各類文物數十件。1983、2009年,通過第二次、第三次全國(guo)文物普查(cha),對(dui)城址進行(xing)了(le)系統的(de)調(diao)查(cha)和(he)著錄。
五家子城址周(zhou)長近3000米,具(ju)有(you)州治規模,可能為(wei)遼信州下轄之州、縣(xian)城。
城(cheng)(cheng)(cheng)(cheng)址(zhi)分為(wei)內(nei)、外二城(cheng)(cheng)(cheng)(cheng),城(cheng)(cheng)(cheng)(cheng)垣均夯(hang)土構筑。外城(cheng)(cheng)(cheng)(cheng)大致呈南北(bei)(bei)(bei)(bei)(bei)向的(de)(de)長(chang)方形(xing)(xing),東(dong)(dong)(dong)(dong)、西兩墻(qiang)(qiang)(qiang)長(chang)約(yue)(yue)(yue)(yue)(yue)823米(mi)(mi)(mi)(mi),南、北(bei)(bei)(bei)(bei)(bei)兩墻(qiang)(qiang)(qiang)長(chang)約(yue)(yue)(yue)(yue)(yue)609.5米(mi)(mi)(mi)(mi),周(zhou)長(chang)約(yue)(yue)(yue)(yue)(yue)2865米(mi)(mi)(mi)(mi)。外城(cheng)(cheng)(cheng)(cheng)殘(can)損(sun)嚴重,城(cheng)(cheng)(cheng)(cheng)垣基(ji)本(ben)無存(cun)(cun)(cun),是否(fou)存(cun)(cun)(cun)有馬面(mian)(mian)(mian)、甕門(men)等(deng)遺跡(ji)(ji)已(yi)不得而知。外城(cheng)(cheng)(cheng)(cheng)四(si)角(jiao)建有角(jiao)樓,東(dong)(dong)(dong)(dong)北(bei)(bei)(bei)(bei)(bei)角(jiao)樓現存(cun)(cun)(cun)好,平(ping)面(mian)(mian)(mian)近圓形(xing)(xing),直徑約(yue)(yue)(yue)(yue)(yue)12米(mi)(mi)(mi)(mi),殘(can)高(gao)(gao)約(yue)(yue)(yue)(yue)(yue)2米(mi)(mi)(mi)(mi),其(qi)余3處(chu)(chu)角(jiao)樓地(di)(di)表(biao)僅(jin)(jin)見稍高(gao)(gao)于地(di)(di)表(biao)的(de)(de)殘(can)跡(ji)(ji)。外城(cheng)(cheng)(cheng)(cheng)東(dong)(dong)(dong)(dong)墻(qiang)(qiang)(qiang)位置,距內(nei)城(cheng)(cheng)(cheng)(cheng)南墻(qiang)(qiang)(qiang)約(yue)(yue)(yue)(yue)(yue)30米(mi)(mi)(mi)(mi)處(chu)(chu),現存(cun)(cun)(cun)一(yi)高(gao)(gao)約(yue)(yue)(yue)(yue)(yue)6米(mi)(mi)(mi)(mi)的(de)(de)圓形(xing)(xing)臺基(ji),疑為(wei)外城(cheng)(cheng)(cheng)(cheng)東(dong)(dong)(dong)(dong)墻(qiang)(qiang)(qiang)甕門(men)的(de)(de)殘(can)跡(ji)(ji)。城(cheng)(cheng)(cheng)(cheng)外10米(mi)(mi)(mi)(mi)處(chu)(chu),東(dong)(dong)(dong)(dong)、西、北(bei)(bei)(bei)(bei)(bei)三面(mian)(mian)(mian)可見護城(cheng)(cheng)(cheng)(cheng)壕(hao)遺跡(ji)(ji),唯東(dong)(dong)(dong)(dong)城(cheng)(cheng)(cheng)(cheng)不見城(cheng)(cheng)(cheng)(cheng)壕(hao)跡(ji)(ji)象,內(nei)城(cheng)(cheng)(cheng)(cheng)位于外城(cheng)(cheng)(cheng)(cheng)的(de)(de)東(dong)(dong)(dong)(dong)北(bei)(bei)(bei)(bei)(bei)角(jiao),東(dong)(dong)(dong)(dong)、北(bei)(bei)(bei)(bei)(bei)兩墻(qiang)(qiang)(qiang)借用外城(cheng)(cheng)(cheng)(cheng)的(de)(de)東(dong)(dong)(dong)(dong)、北(bei)(bei)(bei)(bei)(bei)二墻(qiang)(qiang)(qiang),另筑西墻(qiang)(qiang)(qiang)和(he)南墻(qiang)(qiang)(qiang)而成。內(nei)城(cheng)(cheng)(cheng)(cheng)平(ping)面(mian)(mian)(mian)近正方形(xing)(xing),東(dong)(dong)(dong)(dong)、西兩墻(qiang)(qiang)(qiang)長(chang)約(yue)(yue)(yue)(yue)(yue)341米(mi)(mi)(mi)(mi),南、北(bei)(bei)(bei)(bei)(bei)兩墻(qiang)(qiang)(qiang)長(chang)約(yue)(yue)(yue)(yue)(yue)320.5米(mi)(mi)(mi)(mi),周(zhou)長(chang)約(yue)(yue)(yue)(yue)(yue)1323米(mi)(mi)(mi)(mi)。其(qi)中南墻(qiang)(qiang)(qiang)保存(cun)(cun)(cun)好,基(ji)寬(kuan)約(yue)(yue)(yue)(yue)(yue)8米(mi)(mi)(mi)(mi),現高(gao)(gao)5~6米(mi)(mi)(mi)(mi),其(qi)余3面(mian)(mian)(mian)墻(qiang)(qiang)(qiang)體地(di)(di)表(biao)多僅(jin)(jin)存(cun)(cun)(cun)殘(can)跡(ji)(ji)。內(nei)城(cheng)(cheng)(cheng)(cheng)四(si)角(jiao)構筑有角(jiao)樓,東(dong)(dong)(dong)(dong)北(bei)(bei)(bei)(bei)(bei)角(jiao)樓即為(wei)外城(cheng)(cheng)(cheng)(cheng)東(dong)(dong)(dong)(dong)北(bei)(bei)(bei)(bei)(bei)角(jiao)樓。現存(cun)(cun)(cun)東(dong)(dong)(dong)(dong)南、西南角(jiao)樓,尤以東(dong)(dong)(dong)(dong)南角(jiao)樓較為(wei)完整,平(ping)面(mian)(mian)(mian)近圓形(xing)(xing),基(ji)寬(kuan)約(yue)(yue)(yue)(yue)(yue)16米(mi)(mi)(mi)(mi),高(gao)(gao)約(yue)(yue)(yue)(yue)(yue)8米(mi)(mi)(mi)(mi)。內(nei)城(cheng)(cheng)(cheng)(cheng)未見門(men)址(zhi)與(yu)甕城(cheng)(cheng)(cheng)(cheng)遺跡(ji)(ji)。
外(wai)城(cheng)(cheng)(cheng)地表遺(yi)物豐富,尤以(yi)外(wai)城(cheng)(cheng)(cheng)南側近河(he)一帶(dai)遺(yi)物更為(wei)(wei)(wei)豐富。內城(cheng)(cheng)(cheng)遺(yi)物則非常零星,僅(jin)見(jian)少量(liang)細泥質(zhi)灰(hui)(hui)陶(tao)片和白瓷片,以(yi)及青(qing)磚和布紋瓦殘(can)片。外(wai)城(cheng)(cheng)(cheng)遺(yi)物以(yi)陶(tao)、瓷器(qi)為(wei)(wei)(wei)主。陶(tao)器(qi)以(yi)泥質(zhi)灰(hui)(hui)陶(tao)為(wei)(wei)(wei)主,均輪制(zhi),火候(hou)較高、陶(tao)質(zhi)堅硬。器(qi)形(xing)包括罐(guan)、甕、盆、壺等。陶(tao)器(qi)紋飾多樣,以(yi)多種形(xing)式的(de)(de)附加堆紋為(wei)(wei)(wei)主,還可見(jian)篦齒紋、卷云紋等。另有少量(liang)的(de)(de)夾砂陶(tao),主要出于(yu)城(cheng)(cheng)(cheng)外(wai)南側,器(qi)形(xing)多較小,可能為(wei)(wei)(wei)青(qing)銅時(shi)代遺(yi)物。城(cheng)(cheng)(cheng)內出土瓷器(qi)均為(wei)(wei)(wei)白瓷,胎質(zhi)粗糙(cao),釉色泛黃,器(qi)形(xing)有碗、盤、碟等。
城(cheng)址(zhi)(zhi)雖未(wei)發掘,城(cheng)址(zhi)(zhi)的年代(dai)、性質認定(ding)尚無充分證據,但城(cheng)內出土(tu)遺(yi)物的特點表面,遺(yi)物多為遼(liao)(liao)金(jin)時(shi)期。《遼(liao)(liao)史》信州(zhou)(zhou)條(tiao)下(xia)記錄信州(zhou)(zhou)轄三州(zhou)(zhou)、二縣。五家子城(cheng)址(zhi)(zhi)周長近3000米,具有(you)州(zhou)(zhou)治規模,可能為遼(liao)(liao)信州(zhou)(zhou)下(xia)轄之(zhi)州(zhou)(zhou)、縣城(cheng)。對研究(jiu)當時(shi)的政治、經濟(ji)、軍事、文化、交通等各(ge)方面都(dou)具有(you)較高的歷史價值。