It was first mentioned in written documents dating to 1275 by its German name "Liehtenwalde".
== Etimologija ==Starejši zapisi imena mesta Sevnica so (po letih): 1275 in "Reyn vel in Liehtenwalde", 1309 officium in "Lihtenwalde", 1344 "Lietenueld", 1347 "Liechtenwald", 1581 "Sielnizza".