When I searched for Presbyterian in Ft. Mill, I came up with these. Don't know anything about any of them. I have been inside Unity Presbyterian for a Girl Scout training. It's a pretty large church. Maybe this will get you started.
CHRIST CORNERSTONE PCA, 803-548-2020
100 SPRINGS STREET, FORT MILL SC 29715
COMMUNITY PRESBYTERIAN CHURCH, 803-547-6501
600 NORTH WHITE STREET, FORT MILL SC 29715
GRACE PRESBYTERIAN CHURCH, 803-548-0800
2955 HIGHWAY 160 WEST, FORT MILL SC 29715
RIVERVIEW PRESBYTERIAN CHURCH
124 SUTTON ROAD NORTH, FORT MILL SC 29715
UNITY PRESBYTERIAN CHURCH, 803-547-5543
303 TOM HALL STREET, FORT MILL SC 29715
A lot of folks that I know enjoy Forest Hills Presby:
http://www.foresthill.org/