Fairmont, Virginia, May 4, 1863.The rebel raid into West-Virginia has come and gone. The smoke of battle has drifted away, and the thousand rumors have given place to well-determined facts. I propose to describe briefly what I understand to be the route taken by the raiders after entering our lines until they escaped beyond them; and, with as much detail as time will permit, the engagement at this place. It appears that on Friday and Saturday, the twenty-fourth and twenty-fifth ultimo, the rebels, having driven our small forces from Beverly and Philippi back to Grafton, crossed the railroad at several points between Grafton and Rowlesburgh, and went to Kingwood, in Preston County, thence to Morgantown, which place they reached on Monday, at two P. M. Tuesday morning they left Morgantown, and came up on the east bank of the river to within seven or eight miles of this place, where they were met by another body, which crossed the railroad subsequently. The whole force then returned to Morgantown, crossed the river, spread out over the country, taking every good horse they could find, and concentrated here on Wednesday morning. They crossed Buffalo Creek — which flows from the west and enters the river a mile below town — at Barracksville, and approached town on the Mannington pike. The first positive information of their number and whereabouts, was received from Morgantown on Monday evening. Their number was estimated by a gentleman who witnessed their entree, at five thousand. Before this news came, and while all was vague rumor and perplexing uncertainty, many of our fighting men whom we relied upon as certain to die in “the last ditch,” if die they must, performed “a grand strategical movement,” and “fell back” to a new “base of operations” at Cameron, Moundsville, Wheeling, and various other points in Ohio and Pennsylvania. Those whose lips retained the crimson hue of natural life, and whose knees did not quake like Caesar's with the ague in Spain, remained and busied themselves in hunting up arms, and in making every effort to defend the place against the impending assault. A delegation went to Mannington, and returned on Tuesday morning with two companies of militia and as many guns as were fit for use. The whole defensive force consisted of only three hundred men, made up of companies D and F, One Hundred and Sixth New-York volunteers--one hundred and five men; two companies of the One Hundred and Seventy-sixth Virginia militia--one hundred and seventeen men; thirty-eight men of company A, Sixth Virginia; a few of company B, Sixth Virginia, and about forty citizen soldiers. The rebel army was commanded by General William E. Jones, and consisted, according to his statement, of seven regiments of cavalry, one regiment of mounted infantry, and three hundred mounted sharp-shooters, in all six thousand men,  many of them being of the celebrated Ashby's cavalry. Wednesday morning dawned wet and foggy; our scouts came dashing in and reported the enemy approaching only two or three miles off. One company of militia and most of the armed citizens went out on the hills to meet him. About eight o'clock picket-firing commenced and was kept up briskly for half an hour. The enemy finding we were posted on the hills prepared to rake him severely as he came down the pike along Coal Run, sent a heavy force on the hills to drive us off. In this they succeeded after several of them had been summarily unhorsed. The men from the hills retreated, some to the main force, near the railroad bridge a mile above town, and some to the Palatine end of the Suspension bridge. The latter made a gallant stand and resisted the crossing for nearly an hour. They took shelter in a foundry, and fired from the windows upon the rebel sharp-shooters, who dismounted and took positions in vacant houses, behind fences, stables, and whatever else would conceal their cowardly carcasses from our unerring aim. Thus was the unequal contest continued, until one man, named Coffman, from Bingamon, was fatally wounded, and all but five or six had straggled off. The remainder ceased firing, and each one took care of himself as best ne could. When the firing ceased, the rebels sent over a flag of truce to demand a surrender, but, to their astonishment, they found no one to receive it. They then hastily replaced the plank, which had been removed from the bridge, and crossed over to the number of nearly a thousand, and pushed on up to get in the rear of our men at the railroad bridge. While the fight at the suspension bridge was going on, the rebels disposed their main force for attack at the upper bridge. Our force in defence of the railroad bridge, now about two hundred and seventy-five, had taken up a position half a mile north-west of the bridge, and within gunshot of the road leading to Pruntytown. As the rebel cavalry dashed along this road in order to reach the river above the bridge, they were exposed to a raking and destructive fire, which unhorsed ten or twelve of them. Having crossed at the suspension bridge and occupied the heights at the eastern end of the railroad bridge and gained the river above, they had our men completely surrounded. From his position on the heights to the rear and immediately overlooking the Spartan band, the commanding general called out: “Why the h — ll don't you surrender?” Our boys sent back a defiant response, when he immediately commanded his men to “Rally.” Then began one of the most desperate and unequal contests of this or any other war. For some time the rattle of musketry was incessant. Our men were in open meadows, protected somewhat from the fire in front by ravines, but exposed to the rebel sharp-shooters behind rocks and trees on the right bank of the river. Inch by inch we were forced back to within two hundred yards of the bridge, all the time coolly loading and firing, for the most part after deliberate aim at the cowardly rebels, who, notwithstanding they had twenty to our one, fought Indian fashion, from behind whatever would conceal them. Finding further resistance utterly hopeless, and just as the rebel cavalry were ready for a grand charge, I which must have resulted in the total destruction of the gallant little band, a white flag was raised from a house near by, and the firing ceased. Scarcely had the formalities of the capitulation been completed, when two pieces of ordnance from Mulligan's command at Grafton opened on them from the opposite side of the river. They then double-quicked the prisoners off the field, and placed them in the court-house, where they were paroled about nine o'clock at night. The rebels on the left bank of the river were soon shelled out of range, but those on the same side as the battery made a desperate effort to tear up the road in the rear of the battery to prevent its return. They took up one or more rails, and piled several cords of wood on the track, but, after a sharp engagement, they were driven off by eighty men of company B, One Hundred and Sixth New-York, and a few rounds from the cannon. While the train bearing the battery was behind the hill protecting itself from being cut off and captured, the rebels commenced the destruction of the railroad bridge, which was doubtless the finest structure of the kind in the United States. It was made of iron, supported by four piers of massive stone-work, and was about nine hundred feet long. The iron-work was above the piers, and was supported by tubular columns of cast-iron. In these hollow columns they poured kegs of powder, which they had brought along for the purpose, and in this way the noble structure was blown from the piers into the river. The whole cost of its erection was four hundred and ninety-six thousand dollars, two thirds of which was expended in getting the piers above the high-water mark, owing to the great depth of water and mud above the solid rock. The destruction of this bridge is one of the most serious losses this railroad has sustained during the war. Months must elapse before even a temporary bridge can be erected. The battle we have endeavored to describe, was fought on Wednesday, April twenty-ninth, and was in many respects the most remarkable in the annals of warfare. The great disparity in the numbers engaged; the obstinate, determined resistance made by the Unionists; the length of time they held out; and, stranger still, only one killed and four wounded on our side, while the rebel loss, according to their own admission, was fifty or sixty. Indeed, General Jones told Captain Chamberlain that we had killed and disabled about a hundred of his men. He, as well as the rebel soldiers, complimented us on the gallantry with which we maintained our various positions. Where all who took up arms did so well, it would be invidious to particularize individual acts of heroism. Captain Chamberlain, of company F, One Hundred and Sixth New-York volunteers, had command  of the post, Major Parish of the militia, and each citizen-soldier commanded himself, and as many more as would obey him. Every store in the town was robbed of every thing the thieves fancied. The home rebels, pointed out the private property they wanted destroyed, and it was done. A valuable steam saw-mill, belonging to J. N. Cromwell & Co., was burned. The National printing-office was destroyed because it has been uncompromisingly Union, while the Butternut concern in Morgantown was uninjured, because, as the traitors said, it was on their side and was devoted to their cause. The law and private libraries of Governor Pierpoint were carried into the street in front of his office, and burned; every horse in town and surrounding country was taken. At least five hundred horses were taken out of Marion County alone. Fortunately the Union men had moved their horses out of the neighborhood, while the secesh relied on their opposition to the Government, which has always protected them, for security. Hence in the loss of horses they are by far the greater sufferers, as the raiders were no respecters of persons in making their selections. Some men, who have all along been very desirous to get their “rights,” have had a little foretaste of what their rights are in the estimation of traitors. The miserable copperheads who have been opposing the war, and growling about taxes, have lost more by the men whose rights they are so jealous of, than the Government expects them to pay as taxes for the next ten years.