Reding and Coupigny were somewhat surprised by the bicker of musketry which told them that the French had fallen upon their outposts. But fortunately for them their troops were already getting under arms, and were bivouacking over the lower slopes of the hills in a position which made it possible to extemporize without much difficulty a line of battle, covering the main road and the approaches to Baylen. They hastily occupied the low amphitheatre of hills north and south of the town. Reding deployed to the right of the road, on the heights of the Cerro del Zumacar Chico, Coupigny to its left on the Cerrajon. Their force was of a very composite sort--seventeen battalions of regulars, six of embodied militia, five of new Andalusian levies. The units varied hopelessly in size, some having as few as 350 men, others as many as 1,000. They could also dispose of 1,200 cavalry and sixteen guns. The greater part of the latter were placed in battery on the central and lowest part of the position, north and south of the high road and not far in front of Baylen. The infantry formed a semicircular double line: in front were deployed battalions near the foot of the amphitheatre of hills; in rear, higher up the slope or concealed behind the crest, was a second line in columns of battalions. The cavalry were drawn up still further to the rear. Finally, as a necessary precaution against the possible arrival of Vedel on the scene from La Carolina, Reding placed seven battalions far away to the east, on the other side of Baylen, with cavalry pickets out in front to give timely notice of any signs of the enemy in this quarter. These 3,500 men were quite out of the battle as long as Dupont was the only enemy in sight.
Before it was fully daylight General Chabert and his brigade had thrust back the Spanish outposts. But the strength of the insurgent army was quite unknown to him: the morning dusk still lay in the folds of the hills, and he thought that he might possibly have in front of him nothing but some flying column of insignificant strength. Accordingly, after allowing the whole of his brigade to come up, Chabert formed a small line of attack, brought up his battery along the high road to the middle of the amphitheatre, between the horns of the Spanish position, and made a vigorous push forward. He operated almost entirely to the south of the road, where, opposite Coupigny’s division, the hill was lower and the slope gentler than further north.