Williamson, who plays out of Ashburn, defeated Bruce Tomie of Northumberland Links in a playoff at the provincial championship Saturday at Oakfield to secure the third and final spot on the team.
Nova Scotia champion Myles Creighton, of Ashburn, and runner-up Greg Black, of Oakfield, will also play for Nova Scotia at nationals, while Tomie is the alternate.
Creighton won the Nova Scotia title by a whopping 10 strokes. He shot 4-under-par 68 during his final round to finish the tournament with a 72-hole score of 8-under 280.
Black shot a final-round 1-over 73 to finish at 290, followed by Chester’s Matthew Chandler (68-291), Williamson (73-292) and Tomie (76-292). Chandler declined his spot on the provincial team.
The national championship will be played Aug. 7-10 at the Toronto and Islington golf clubs in Mississauga.
Truro’s Robert Watt led a contingent of Colchester County golfers. Watt carded a final-round 78 (306) and finished tied for 31st. Other local players who made the cut were Truro’s Chris Topshee (80-308), Cory Pothier (74, 311), Robert Jeffcock (79-313) and Isaac McNaughton (84-325) and Brookfield’s Michael Penny (86-329).