From BiblePortal Wikipedia

Hastings' Dictionary of the Bible [1]

SIHON . A king of the Amorites at the time of the conquest of Canaan. His dominion lay beyond the Jordan, between Jabbok on the N. and Arnon on the S., extending eastward to the desert (  Judges 11:22 ). He refused to allow Israel to pass through his land, and was defeated at Jahaz (  Numbers 21:21-24 ,   Deuteronomy 2:26-36 ,   Judges 11:19-22 ). Heshbon , his capital, was taken; and his land, along with that of Og king of Bashan, became the possession of Reuben, Gad, and the half tribe of Manasseh. Frequent reference is made to his defeat (  Numbers 32:33 ,   Deuteronomy 1:4;   Deuteronomy 3:2;   Deuteronomy 3:6;   Deuteronomy 4:46-47;   Deuteronomy 29:7;   Deuteronomy 31:4 ,   Joshua 2:10;   Joshua 9:10;   Joshua 12:2;   Joshua 13:10;   Joshua 13:21; Jos 13:27 ,   1 Kings 4:19 ,   Nehemiah 9:22 ,   Psalms 135:11;   Psalms 136:19 ). Sihon in   Jeremiah 48:45 stands for Heshbon, the city of Sihon.

W. F. Boyd.

Fausset's Bible Dictionary [2]

King of the Amorites. Shortly before Israel's approach he had dispossessed Moab of all their territory N. of Arnon. An Israelite poet celebrates Sihon's victory, glorifying Heshbon as the city from whence "a flame" went forth "consuming Ar of Moab," so that "Moab's sons their idol ("Chemosh") rendered fugitives, and yielded his daughters into captivity unto Sihon"! then by a sudden startling transition the poet introduces Israel's triumph in turn over Sihon. "We ("Israelites") have shot at them, Heshbon is perished even unto Dibon, and we have laid them waste even unto Nophah, with fire even unto Medeba." Israel begged leave to pass peaceably through the Amorite land by the king's highway, but "Sihon gathered all his people" and came to Jahaz (Between Dibon And Medeba) and fought against Israel and was defeated. Churlishness and unprovoked violence bring their own punishment ( Proverbs 16:18;  Proverbs 18:12;  Numbers 21:21-31). So Israel gained all the Amorite territory, from the Arnon to the Jabbok. Josephus says that every man in the nation fit to bear arms fought in the Amorite army against Israel (Ant. 4:, section 2). The struggle was a desperate one; no mere human force enabled Israel, heretofore unused to warfare, to subdue so formidable a king and conqueror as Sihon. Pride of conquest was his snare.

Easton's Bible Dictionary [3]

 Numbers 21:21-30 Deuteronomy 2:24-37

The country from the Jabbok to Hermon was at this time ruled by Og, the last of the Rephaim. He also tried to prevent the progress of the Israelites, but was utterly routed, and all his cities and territory fell into the hands of the Israelites (Compare  Numbers 21:33-35;  Deuteronomy 3:1-14;  Psalm 135 ::  1012-12;  136:17-22 ).

These two victories gave the Israelites possession of the country on the east of Jordan, from the Arnon to the foot of Hermon. The kingdom of Sihon embraced about 1,500 square miles, while that of Og was more than 3,000 square miles.

Morrish Bible Dictionary [4]

King of the Amorites, who, after his victory over the Moabites, was defeated and slain, with his army, by the Israelites. His territory was on the east of the Jordan, from the Arnon to the Jabbok: it was possessed by the Israelites. The victory is commemorated in two of the Psalms.  Numbers 21:21-35;  Numbers 32:33;  Deuteronomy 1:4;  Deuteronomy 2:24-36;  Deuteronomy 3:2-6;  Joshua 12:2;  Judges 11:19-22;  Psalm 135:11;  Psalm 136:19;  Jeremiah 48:45 .

Smith's Bible Dictionary [5]

Si'hon. (Warrior). King of the Amorites, when Israel arrived on the borders of the Promised Land.  Numbers 21:21. (B.C. 1451). Shortly before the time of Israel's arrival, he had dispossessed the Moabites of a splendid territory, driving them south of the natural bulwark of the Amen.  Numbers 21:26-29. When the Israelite host appeared, he did not hesitate or temporize like Balak, but, at once, gathered his people together and attacked them. But the battle was his last. He and all his host were destroyed, and their district from Amen to Jabbok became, at once, the possession of the conqueror.

People's Dictionary of the Bible [6]

Sihon ( Sî'Hon ), Sweeping Away. A king of the Amorites at Heshbon, who was slain, and his kingdom taken by the Hebrews.  Numbers 21:21-31;  Deuteronomy 2:26;  Psalms 135:11-12;  Jeremiah 48:45.

American Tract Society Bible Dictionary [7]

King of the Amorites at Heshbon, on refusing passage to the Hebrews, and coming to attack them, was himself slain, his army routed, and his dominions divided among Israel,  Numbers 21:21-34   Deuteronomy 2:26-36 .

Hawker's Poor Man's Concordance And Dictionary [8]

King of the Amorites: his history we have,  Numbers 21:21, etc. If the word be, as is supposed, its own root; it means rooting out.

Holman Bible Dictionary [9]

 Deuteronomy 2:26 Numbers 21:23

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [10]

(Heb. Sichon', zx סַיחוֹן [or סיחֹ ,  Numbers 21:21;  Numbers 21:23;  Numbers 21:26;  Numbers 21:28;  Numbers 21:34;  Numbers 32:33;  Deuteronomy 1:4;  Deuteronomy 2:24;  Deuteronomy 2:31-32;  Deuteronomy 3:2;  Deuteronomy 3:6;  Deuteronomy 4:46;  Deuteronomy 29:7;  Joshua 2:10;  Jeremiah 48:45], Sweeping away, i.e. Warrior [Gesen.], or Bold [Furst]

Sept. Σηών v.r. Σιών ; Josephus, Σιχών ), the king of the Amorites when Israel arrived on the borders of the Promised Land. ( Numbers 21:21). B.C. 1618. He was evidently a man of great courage and audacity. Shortly before the time of Israel's arrival, he had dispossessed the Moabites of a splendid territory, driving them south of the natural bulwark of the Arnon with great slaughter and the loss of a great number of captives (21:26-29). When the Israelitish host appears, he does not hesitate or temporize like Balak, but at once gathers his people together and attacks them. But the battle was his last. He and all his host were destroyed, and their district from Arnon to Jabbok became at once the possession of the conqueror. Josephus ( Ant. 4, 5, 2) has preserved some singular details of the battle, which have not survived in the text either of the Hebrew or Sept. He represents the Amoritish army as containing every man in the nation fit to bear arms. He states that they were unable to fight when away. from the shelter of their cities, and that being especially galled by the slings and arrows of the Hebrews, and at last suffering severely from thirst, they rushed to the stream and to the shelter. of the recesses of the ravine of the Arnon. Into these recesses they were pursued by their active enemy and slaughtered in vast numbers. Whether we accept these details or not, it is plain, from the manner in which the name of Sihon fixed itself in the national mind, and the space which his image occupies in the official records and in the later poetry of Israel, that he was a truly formidable chieftain ( Deuteronomy 31:4;  Joshua 9:10;  Joshua 12:2;  Joshua 12:5;  Joshua 13:10;  Joshua 13:21;  Joshua 13:27;  Judges 11:19-21;  1 Kings 4:19;  Nehemiah 9:22;  Psalms 135:11;  Psalms 136:19). It is probable that a trace of the name still remains, in the Jebel Shihan, a lofty and conspicuous mountain just to the south of the Wady Mojeb.

International Standard Bible Encyclopedia [11]

sı̄´hon ( סיחון , ṣı̄ḥōn ): King of the Amorites, who vainly opposed Israel on their journey from Egypt to Palestine, and who is frequently mentioned in the historical books and in the Psalms because of his prominence and as a warning for those who rise against Yahweh and His people (  Numbers 21:21 , and often;  Deuteronomy 1:4;  Deuteronomy 31:4;  Joshua 2:10;  Judges 11:19 ,  Judges 11:20 ,  Judges 11:21;  1 Kings 4:19;  Nehemiah 9:22;  Psalm 135:11;  Psalm 136:19;  Jeremiah 48:45 ).

Kitto's Popular Cyclopedia of Biblial Literature [12]

Si´hon (sweeping away; i.e. a warrior sweeping all before him), the king of the Amorites, reigning at Heshbon, who was destroyed, and his kingdom subjugated, in the attempt to resist the progress of the Israelites through his dominions (; , sq.) [AMORITES].