Almost a suburb of Charlotte
When I was growing up Rock Hill was most famous as a place where couples who were too young to marry in NC would (sometimes literally) sneak across the state line to get married. Today it is a small city of about 50,000 population and is not a difficult jaunt from Charlotte at all. Many Rock Hill residents work in Charlotte.
Perhaps the most famous thing about Rock Hill today is Winthrop University. Winthrop is a relatively small university but it is well regarded academically and, especially in recent years, it has developed a very recognizable basketball program.
On the other hand the most picturesque aspect of Rock Hill may be its Glencairn Garden park, small but very lovely, with lots of trees, shrubs, and flowers. There is no admission fee to the Garden and it is open during daylight hours only. As of July, 2010, you can add the York County Riverwalk Trail as another beautiful site where you can enjoy the beauty of the Palmetto State at a leisurely pace, or take advantage of opportunities for exercise.
If you want something a little more active try Cherry Park. It is at least ten times the size of Glecairn Garden and features sveral athletic fields, which always seem to be in use, plus picnic areas, and walking (or biking) trails.