Sesquicentennial State Park, Columbia, SC
Sesquicentennial State Park ("Sesqui", for short), in Columbia, SC, is a good example of a geocaching park. There are a dozen caches, including several multi-caches and one puzzle cache, in an area just over one square mile. The park has a trail system on which the caches are placed, minimizing the amount of bushwhacking necessary to find the caches.
Sesquicentennial State Park is loaced in Columbia, South Carolina. Though it was once on the northern edge of the city, the city has grown around the park, making the area outside the park boundaries very urban. The park is easily accessable from I-20 or I-77.
Sesquicentennial State Park does charge admission. Please see the park's website (link below) for full details.