Sorenstam shot a bogey-free 8-under-par, 64 in Friday's second round for a 36-hole total of 13- under-par, 131. It is her biggest 36-hole lead in a four-round event in four years.
Heather Bowie is in second place at 7- under-par, 137, followed by fellow American Lorie Kane, who is in third place another shot back at 138.
Other top players faded from contention Friday after struggling on the Eagle's Landing course.
First round leader Laura Davies of Britain hit a 76 to land 11 shots behind Sorenstam. Former world number one Karrie Webb of Australia and American Cristie Kerr both went over par in the second round, and are 10 strokes off the lead. And defending champion Jennifer Rosales of the Philippines is 13 shots back after carding a 76.
Some information for this report provided by AP.