International Standard Bible Encyclopedia 
gil´ē̇ - ad ( הגּלעד , ha - gil‛ādh , "the Gilead"): The name is explained in Genesis 31:46 , Genesis 31:51 , as derived from Hebrew gal , "a cairn," and ‛ēdh , "witness," agreeing in meaning with the Aramaic yeghar - sāhădhūthā ). The Arabic jileād means "rough," "rugged."
(1) A city named in Hosea 6:8; Hosea 12:11 , possibly to be identified with Gilead near to Mizpah ( Judges 10:17 ). If this is correct, the ancient city may be represented by the modern Jil‛ād , a ruin about 5 miles North of es - Salṭ .
(2) A mountain named in Judges 7:3 . Gideon, ordered to reduce the number of men who were with him, commanded all who were "fearful and trembling" to "return and depart from Mt. Gilead." the Revised Version, margin reads "return and go round about from Mt. Gilead." Gideon and his army lay to the South of the plain of Jezreel on the lower slopes of Gilboa. It has been suggested (Studer, Comm ., at the place) that, as the Midianites lay between the men of the northern tribes and their homes, they were told to cross the Jordan, make a détour through Gilead, and thus avoid the enemy. Possibly, however, we should read Gilboa for Gilead; or part of the mountain may have borne the name of Gilead. The last suggestion is favored by the presence of a strong spring under the northern declivity of Gilboa, nearly 2 miles from Zer‛ı̄n , possibly to be identified with the Well of Harod. In the modern name, ‛Ain Jalūd , there may be an echo of the ancient Gilead.
(3) The name is applied generally to the mountain mass lying between the Yarmūk on the North, and Wādy Ḥesbān on the South; the Jordan being the boundary on the West, while on the East it marched with the desert.
1. The Land of Gilead
Mount Gilead - literally, "Mount of the Gilead" - may refer to some particular height which we have now no means of identifying ( Genesis 31:23 ). The name Jebel Jil‛ād is still, indeed, applied to a mountain South of Nahr ez - Zerḳā and North of es - Salṭ ; but this does not meet the necessities of the passage as it stands. The same expression in Deuteronomy 3:12 obviously stands for the whole country. This is probably true also in Song of Solomon 4:1 . The name Gilead is sometimes used to denote the whole country east of the Jordan ( Genesis 37:25; Joshua 22:9; 2 Samuel 2:9 , etc.). Again, along with Bashan, it indicates the land East of Jordan, as distinguished from the Moab plateau ( Deuteronomy 3:10; Joshua 13:11; 2 Kings 10:33 ).
In the North Gilead bordered upon Geshur and Maacah ( Joshua 13:11 , Joshua 13:13 ); and here the natural boundary would be formed by the deep gorge of the Yarmūk and Wādy esh - Shellāleh . In pre-Israelite times the Jabbok ( Nahr ez - Zerḳā' , which cuts the country in two, divided the kingdom of Sihon from that of Og ( Deuteronomy 3:16; Joshua 12:2 ). The frontiers between the tribes of Reuben, Gad and Manasseh cannot be indicated with any certainty. Probably they varied at different times (compare Joshua 13:24; 1 Chronicles 5:8 , 1 Chronicles 5:9 , 1 Chronicles 5:11 , 1 Chronicles 5:16 ). It greatly increases the difficulty that so many of the cities named are still unidentified. But in any case it is clear that the bulk of Gilead fell to Gad, so that Gilead might stand for Gad ( Judges 5:17 ). Havvoth-Jair (which see), "the villages of Jair," lay in Gilead ( Judges 10:4 ). The modern division of the country follows the natural features. From the Yarmūk to Nahr ez - Zerḳā is the district of ‛Ajlūn ; and from the Zerḳā to the Arnon is el - Belḳā .
The geological formation is the same as that of Western Palestine, but the underlying sandstone, which does not appear West of the Jordan, forms the base slopes of the chain of Moab and Gilead, and is traceable as far as the Jabbok. It is covered in part by the more recent white marls which form the curious peaks of the foothills immediately above the Jordan valley; but reaches above them to an elevation of 1,000 ft. above the Mediterranean on the South, and forms the bed of the Buḳei‛a basin farther East, and 1,000 ft. higher. Above this lies the hard, impervious dolomite limestone which appears in 'the rugged hills round' the Jabbok and in Jebel ‛Ajlūn , rising on an average 1,500 ft. above the sandstone and forming the bed of the copious springs. It also dips toward the Jordan valley, and the water from the surface of the plateau, sinking down to the surface of their formation, bursts out of the hill slopes on the West in perennial brooks. It was from the ruggedness of this hard limestone that Gilead obtained its name. Above this again is the white chalk of the desert plateau, the same as that found in Samaria and Lower Galilee, with bands of flint or chert in contorted layers, or strewn in pebbles on the surface. Where this formation is deep the country is bare and arid, supplied by cisterns and deep wells. Thus the plateau becomes desert, while the hill slopes abound in streams and springs; and for this reason Western Gilead is a fertile country, and Eastern Gilead is a wilderness (Conder, Db , under the word).
The uplands of Gilead may be described as the crumpling of the edge of the great eastern plateau ere it plunges into the Ghōr . The average height of the range is about 4,000 ft. above the Jordan valley, or 3,000 ft. above the Mediterranean. The greatest height is toward the South, where it culminates in Jebel Osh‛a (3,597 ft.), to the North of es - Salṭ . This mountain commands a most spacious view. To the East of it lies the hollow (an old lake bottom) of el - Buḳei‛a , fully 1,500 ft. lower. In the North we have Jebel Hakart (3,408 ft.) W, of Reimūn . Almost as high (3,430 ft.) is Jebel Kafkafah , about 12 miles to the Northeast. A striking point (2,700 ft.) fully 2 miles Northwest of ‛Ajlūn , is crowned by Ḳal‛at er - Rabad , whence again a view of extraordinary extent is gained.
5. Streams and Products
The Yarmūk and the Zerḳā - see Jabbok - are the main streams, but almost every valley has its perennial brook. While not so rich as the volcanic loam in the North and in and the South, the soil of Gilead amply repays the labor of the husbandman. Of flowers the most plentiful are the phlox, the cistus and the narcissus. Hawthorn, mastic and arbutus abound, while many a glen and slope is shady with shaggy oak woods, and, in the higher reaches, with pines. The streams are fringed with oleander. The monotony of the stony plateau is broken by clumps of the hardy white broom. In the lower ground are found the tamarisk and the lotus, with many a waving cane-brake. The scenery is more beautiful and picturesque than that of any other district of Palestine. The soil is not now cultivated to any great extent; but it furnishes ample pasture for many flocks and herds ( Song of Solomon 6:5 ).
The Ishmaelites from Gilead ( Genesis 37:25 ) were carrying "spicery and balm and myrrh." From old time Gilead was famed for its Balm (which see). The lōṭ , translated "myrrh" in the above passage, was probably the gum produced by the Cistus ladaniferus , a flower which still abounds in Gilead.
After the conquest, as we have seen, Gilead passed mainly into the hands of Gad. An Ammonite attack was repulsed by the prowess of Jephthah ( Judges 11:1 ); and the spite of the Ephraimites was terribly punished ( Judges 12:1 ). Gilead at first favored the cause of Ishbosheth ( 2 Samuel 2:9 ), but after the murder of that prince the Gileadites came with the rest of Israel to David ( 2 Samuel 5:1 ). By the conquest of the fortress Rabbah, which the Ammonites had continued to hold, the land passed finally under the power of David ( 2 Samuel 12:26 ). David fled to Mahanaim from Absalom, and that rebel prince perished in one of the forests of Gilead ( 2 Samuel 17:24; 2 Samuel 18:6 ). Joab's census included Gilead ( 2 Samuel 24:6 ). Solomon had two commissariat districts in Gilead ( 1 Kings 4:13 f,19). Before Ramoth-gilead, which he sought to win back from the Syrians who had captured it, Ahab received his death wound ( 1 Kings 22:1 ). The Syrians asserted their supremacy in Gilead ( 2 Kings 10:32 f) where Moab and Israel had contended with varying fortune (M S). At length Tiglath-pileser overran the country and transported many of the inhabitants ( 2 Kings 15:29 ). This seems to have led to a reconquest of the land by heathenism, and return to Gilead was promised to Israel ( Zechariah 10:10 ).
At a later time the Jewish residents in Gilead were exposed to danger from their heathen neighbors. On their behalf Judas Maccabeus invaded the country and met with striking success ( 1 Maccabees 5:9 ff). Alexander Janneus, who had subdued Gilead, was forced to yield it again to the king of Arabia ( Ant. , Xiii , xiv, 2; Bj , I, iv, 3). During the Roman period, especially in the 2nd and 3centuries ad, the land enjoyed great prosperity. Then were built such cities as Gadara and Gerasa, which are still imposing, even in ruins. The appearance of the Moslem armies was the signal for its decay. Attempts were made to recover it for Christianity by Baldwin I (1118 ad) and Baldwin 2 (1121 ad); and the Crusaders left their mark in such strong-holds as Ḳal‛at er - Rabad and the castle at es - Salṭ . With the reassertion of Moslem supremacy a curtain falls over the history of the district; and only in comparatively recent times has it again become known to travelers. The surveys directed by the Palestine Exploration Fund, in so far as they have been carried out, are invaluable. North of the Jabbok are many villages, and a fair amount of cultivation. Es Salṭ is the only village of any importance in the South. It is famous for its raisins. Its spacious uplands, its wooded and well-watered valleys have been for centuries the pasture-land of the nomads.
Useful information will be found in Merrill, East of the Jordan ; Oliphant, Land of Gilead ; Thomson, Lb ; and especially in Conder, Heth and Moab , and in Memoirs of the Survey of Eastern Palestine.