On September 7, Gates ordered his army to march north. A site was selected for its defensive potential that was known as Bemis Heights, just north of Stillwater and about south of Saratoga; the army spent about a week constructing defensive works designed by Polish engineer Tadeusz Kościuszko. The heights had a clear view of the area and commanded the only road to Albany, where it passed through a defile between the heights and the Hudson River. To the west of the heights lay more heavily forested bluffs that would present a significant challenge to any heavily equipped army.