With the tools I have at hand, I believe the location of Ivey Hill (aka Prairie Mount) and the site of the largest of the engagements in the Sooy Smith Expedition is located here:

http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=okolona,+ms&sll=37.0625,-95.677068&sspn=34.534108,42.099609&ie=UTF8&ll=34.052517,-88.831158&spn=0.070544,0.082226&z=13&layer=c&cbll=34.052426,-88.831094&panoid=RCuOiFqAtuPXEB9MwUC05w&cbp=12,0,,2,5

You can't read the marker with this zoom, but is is approximately 6 miles from Okolona on "the Pontotoc road", now Highway 41. Also, just across the road is the Prairie Mount Church, which must be a reference to the geological feature, described as a ridge, where the Union forces made their stand.

http://maps.google.com/maps?f=q&source=s_q&hl=en&q=Prairie+Mt+Church,+Okolona,+Chickasaw,+Mississippi+38860&sll=34.022645,-88.786354&sspn=0.033221,0.041113&ie=UTF8&cd=1&geocode=FV6rBwIdxV60-g&split=0&ll=34.067165,-88.842487&spn=0.066408,0.082226&z=13&iwloc=A

I'm also trying to locate the heavy skirmish, nearly equal to Ivey's Hill in its ferocity, which occurred south of Okolona.

This is not definitive information. Maybe others can contribute more.

Jim Martin