From BiblePortal Wikipedia

Hastings' Dictionary of the Bible [1]

Elasa ( 1Ma 9:5 ). The scene of the defeat and death of Judas Maccabæus. The site may be at the ruin Il’asa , near Beth-horon.

International Standard Bible Encyclopedia [2]

el´a - sa , el - ē̇ - ā´sa ( Ἀλασά before the battle in which he was overwhelmed and slain (1 Macc 9:5). It probably corresponds to the modern Khirbet il‛asā , between the two Beth-horons.