In 1913 Siwanoy Country Club embarked on its third major building effort, this time laying out an 18-hole course and clubhouse after the property earned the endorsement of Donald Ross, who confirmed it was well-suited for a full-length course. Ross — who would go on to design over 600 courses in the first half of the 20th century, including four at Pinehurst, North Carolina — planned and oversaw construction on the Manor Property that year. Much of the routing he established remains the backbone of today’s Siwanoy layout, though a few of his originally placed bunkers and sand traps were later removed. The initial course measured 6,251 yards and was rated at par 73 in 1914, a rating since adjusted downward to par 71.