Here are Campbell's American designs in approximate chronological order. There are three other courses - Warren Farm, Pride's Crossing & Appleton Farm - I suspect he was involved in laying out but have not found the confirming documentation as yet.
The Country Club, MA 1894
Essex County, MA 1894
Myopia Hunt, MA 1894
Nahant, MA 1894
Wakefield, MA 1894
Merion Cricket, PA 1896
Belmont Cricket, PA 1896
Philadelphia, PA 1896
Franklin Park, MA 1896
Huntingdon Valley, PA 1897
Winchester, MA 1897
Salem, MA 1897
Topsfield, MA 1897
Hawthorn, MA 1897
Cambridge, MA 1897
Wakefield Park, MA 1897
Bridgewater, MA 1897
Beaver Meadow, NH 1897
Wannamoisett, RI 1898
Tatnuck, MA 1898
Moorestown Field, NJ 1898