The meaning is that, taking up the lamentation of Heshbon, the Moabites break forth into a wail, heard as far as Elealeh, scarcely two miles distant Numbers 32:37, but thence spreading over the land to towns on the southern and southwestern borders of the land.
An heifer of three years old - Applied in Isaiah 15:5 to Zoar, but here to Horonaim. Some take “an heifer” as a proper name, and render it: “Eglah for the third part” (compare Isaiah 19:24). Zoar, Horonaim, and Eglah formed a tripolis, or confederacy of three towns, and Eglah might therefore be put after either one or the other.
Nimrim - Probably the Wady-en-Nemeirah at the southeastern end of the Dead Sea.