An acre is equal to 4,840 square yards, so 35 acres is equal to 169,400 square yards. This is equivalent to about .055 square miles. It takes about 640 acres to equal 1 square mile.
The area covered by an acre is roughly equal to 90 percent of an American football field. In the Middle Ages, an acre was considered to be how much land a yoke of oxen could plough in one day. A square acre is approximately 69.57 yards on a side, but since an acre is a measure of area, it has no prescribed shape. Technically, a plot of land 1 yard wide and 4,840 yards long could be called an acre.