Acres to Square Mils: the quick answer
1 ac = 6,272,640,000,000 mil²
1 acre equals 6,272,640,000,000 square mils
To convert acres to square mils, multiply the value by 6,272,640,000,000. To go the other way, multiply square mils by 1.59423 × 10⁻¹³ to get acres.