Useful Facts. A surveyor's chain is 4 poles, or 17 feet, divided into a hundred links, or 792 inches. A square chain is 16 square poles,, and ten square chains is an acre. Four roods are an acre, each containing 1,240 square yards, or 37,787 feet, or 24 yards, 28 inches on each side. A pole is 5 1/2 yards each way. A square mile, 1,760 yards each way, i- 640 acres ; half a mile, or 880 yards each way, is 160 acres; a quarter of a mile, 440 yards each way, is a park or farm of 40 acres ; and a furlong, or 220 yards each way, is 10 acres.