該(gai)保護(hu)區(qu)地(di)理位置(zhi)為(wei)(wei):東經126°35′~128°02′,北(bei)(bei)緯42°06′~43°51′。總(zong)面(mian)(mian)(mian)(mian)積約(yue)114.5萬(wan)公頃。其(qi)中林地(di)82.3萬(wan)公頃,占總(zong)面(mian)(mian)(mian)(mian)積71.9%;水域(yu)5.7萬(wan)公頃,占總(zong)面(mian)(mian)(mian)(mian)積的(de)5.0%。三湖保護(hu)區(qu)地(di)處長白山(shan)(shan)(shan)(shan)余脈(mo)(mo)。四面(mian)(mian)(mian)(mian)環山(shan)(shan)(shan)(shan),西面(mian)(mian)(mian)(mian)是吉林哈達嶺(ling)山(shan)(shan)(shan)(shan)脈(mo)(mo),北(bei)(bei)面(mian)(mian)(mian)(mian)是老(lao)爺嶺(ling)山(shan)(shan)(shan)(shan)脈(mo)(mo),東面(mian)(mian)(mian)(mian)是威虎嶺(ling)和黃泥嶺(ling)山(shan)(shan)(shan)(shan)脈(mo)(mo),南面(mian)(mian)(mian)(mian)是老(lao)嶺(ling)山(shan)(shan)(shan)(shan)脈(mo)(mo)。地(di)勢(shi)東南高(gao)西北(bei)(bei)低(di)(di)。地(di)貌(mao)多為(wei)(wei)中(高(gao))山(shan)(shan)(shan)(shan)?低(di)(di)(丘)山(shan)(shan)(shan)(shan)?崗(gang)(臺(tai))川類。其(qi)面(mian)(mian)(mian)(mian)積比例(li)大致為(wei)(wei)七山(shan)(shan)(shan)(shan)二(er)崗(gang)一川。境內山(shan)(shan)(shan)(shan)巒起伏,綿(mian)延不斷,溝(gou)壑縱橫,異峰突兀。海拔800米以上的(de)山(shan)(shan)(shan)(shan)峰有80余座,其(qi)最高(gao)為(wei)(wei)南樓山(shan)(shan)(shan)(shan),海拔1404.8米,在樺甸市常山(shan)(shan)(shan)(shan)境內;最低(di)(di)為(wei)(wei)豐滿壩(ba)下,海拔約(yue)190米。該(gai)地(di)區(qu)地(di)質構(gou)成多為(wei)(wei)玄武(wu)巖(yan)、石(shi)灰(hui)巖(yan)、土(tu)(tu)(tu)壤(rang)(rang)類型為(wei)(wei)暗棕(zong)壤(rang)(rang)、白漿土(tu)(tu)(tu)、草甸土(tu)(tu)(tu)、棕(zong)色(se)森林土(tu)(tu)(tu)、泥炭土(tu)(tu)(tu)等。
三湖保護區(qu)(qu)處于北溫(wen)(wen)(wen)(wen)(wen)帶大陸(lu)性季(ji)風氣(qi)候區(qu)(qu)內。四季(ji)分明,年(nian)(nian)、日較差大。春季(ji)干燥多(duo)風?夏季(ji)溫(wen)(wen)(wen)(wen)(wen)熱(re)多(duo)雨?秋(qiu)季(ji)晴爽?冬季(ji)嚴(yan)寒?年(nian)(nian)平均(jun)氣(qi)溫(wen)(wen)(wen)(wen)(wen)在(zai)1.9℃~4.4℃之間?極端高溫(wen)(wen)(wen)(wen)(wen)36.6℃,極端低溫(wen)(wen)(wen)(wen)(wen)-45℃。年(nian)(nian)≥10℃積溫(wen)(wen)(wen)(wen)(wen)為1900℃~2800℃,并呈由南(nan)至(zhi)北增加趨(qu)勢?年(nian)(nian)日照時(shi)數2350~2450小時(shi)?年(nian)(nian)降水量由南(nan)向北略有(you)減少,為834~673毫米之間。無霜期大致(zhi)為110~130天。一月平均(jun)氣(qi)溫(wen)(wen)(wen)(wen)(wen)約為-18℃,七月平均(jun)氣(qi)溫(wen)(wen)(wen)(wen)(wen)約為20℃左右(you)。該區(qu)(qu)夏季(ji)盛(sheng)行西(xi)(xi)南(nan)風,冬季(ji)盛(sheng)行西(xi)(xi)北風。
保護(hu)區(qu)由于受到三個湖泊及森林(lin)等因素影響,又具有湖泊氣候、谷地氣候和森林(lin)氣候的復合特征。