They then pushed ahead fifteen miles until they encountered the British defensive line on the Chippawa River where it flows into the Niagara.
The field was like a park, with open, grassy spaces and a belt of woodland which served as a green curtain to screen the movements of both armies.

Riall boldly assumed the offensive, although he was aware that he had fewer men.

His instructions intimated that liberties might be taken with the Americans which would seem hazardous "to a military man unacquainted with the character of the enemy he had to contend with, or with the events of the last two campaigns on that frontier." The deduction was unflattering but very much after the fact.
The British attack was unlooked for.

It was the Fourth of July and in celebration Winfield Scott had given his men the best dinner that the commissary could supply and was marching them into a meadow in the cool of the summer afternoon for drill and review.

The celebration, however, was interrupted by firing and confusion among the militia who happened to be in front, and Scott rushed his brigade forward to take the brunt of the heavy assault.