He encountered the enemy, but was ordered in and did not engage them.
That portion of the country around Chancellorsville within the Union lines on the morning of May 2d, may, with some exceptions, be described as a plain, covered by dense thickets, with open spaces in the vicinity of the houses, varied by the high ground at Talley's on the west and by the hills of Fairview and Hazel Grove on the south, and terminating in a deep ravine near the river.

Our general line was separated from that of the enemy by small streams, which principally ran through ravines, forming obstacles useful for defensive purposes.

This was the case on the east and south, but on the west, where Howard's line terminated, there was nothing but the usual thickets to impede the enemy's approach.
As the narrative proceeds, the position of the Confederate army, who held the broken ground on the other side of those ravines, will be more particularly described.
After all, a defensive battle in such a country is not a bad thing, for where there are axes and timber it is easy to fortify and hard to force the line; always provided that free communications are kept open to the central reserve and from one part of the line to another.

It must be confessed that the concealment of the thickets is also favorable to the initiative, as it enables the attacking party to mass his troops against the weak parts without being observed.

Hooker probably thought if Lee assailed a superior force in an intrenched position he would certainly be beaten; and if he did not attack he would soon be forced to fall back on his depots near Richmond for food and ammunition.