From BiblePortal Wikipedia

Smith's Bible Dictionary [1]

Az'mon. (Strong). A place named as being on the southern boundary of the Holy Land, apparently near the torrent of Egypt ( Wadi El-Arish ).  Numbers 34:4-5;  Joshua 15:4. It has not yet been identified.

Hastings' Dictionary of the Bible [2]

Azmon . An unknown place on the border of Judah (  Numbers 34:4 ,   Joshua 15:4 ); called in   Joshua 15:29;   Joshua 19:3 Ezem .

Morrish Bible Dictionary [3]

Place on the south west frontier of Palestine, apparently near the Wady el-Arish, the torrent of Egypt.  Numbers 34:4,5;  Joshua 15:4 .

Fausset's Bible Dictionary [4]

On the S. border of Palestine, near the torrent of Egypt, wady el Arish ( Numbers 34:4-5;  Joshua 15:4).

Holman Bible Dictionary [5]

 Numbers 34:4 Joshua 15:4

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [6]

(Hebrews Atsmon', עִצְמוֹן ', Strong; Sept. Ἀσεμωνᾶ , Εελμωνάν ), a place on the southern border of Palestine, between Hazar-adar (beyond a bend at Karkaa) and "the river of Egypt" ( Numbers 34:4-5;  Joshua 15:4). The site is perhaps marked by the ruins on a hill near Wady Es-Shutin (Robinson, Researches, 1, 296), near the junction of Wady Futeis with Wady Ruhaibeh, (See Tribe), about half way between Elusa and Rehoboth (Van de Velde's Jiap). (See Heshmon).

International Standard Bible Encyclopedia [7]

az´mon עצמון , ‛acmōn  ; Ἀσεμώνα , Asemō̇na , "strong": On the Southwest border of Israel ( Numbers 34:4 ,  Numbers 34:5;  Joshua 15:4 ). Trumbull identifies it with 'Ain el-Qaseimeh, Northwest of Kadesh Barnea ( Kad. Baruch ., 117, 289 f).