Firing 1-under the card in the final round was enough for Cabban to collect his biggest win of 2016 with a two round total of 6-under 138.
Cabaan was happy to see his hard work translating into results on the Choice PGA Pro-Am Series.
"This is a result of lot's of hard work in recent times," said Cabban.
Townsend fired the low round of the tournament shooting a 6-under 66 to overcome his first round 73 to finish outright second ahead of 2015 PGA Tour of Australasia Player of the Year Matthew Millar, rookie Dale Brandt-Richards and the 2015 NSW/ACT Order of Merit winner Callan O'Reilly.
Other notable finishes were had by Steve Conran who finished in a tie for 8th and Dimi Papadatos who fell out of contention on Tuesday with a 4-over 76 leaving him in 16th place.
The Mulpha Castle Hill Pro-Am was recently awarded the NSW/ACT City Pro-Am of the Year for 2015, making it three consecutive years of success in the category.
"It was a great honour to receive the award and worthy recognition for all the hard work which the club management and staff put in to the tournament," said David Northey, Head PGA Professional at Castle Hill.
From Castle Hill many players will head to Barnwell Park Golf Club in Inner West Sydney for the 2016 Option Finance Barnwell Park Pro-Am which starts on Thursday ahead of the Easter break.
Headlines at a glance
Fraser making Rio move
Marcus Fraser not only finished top Australian at the European Tour's BMW International Open he made up a little ground on Scott Hend in the race to r...
Baddeley continues to climb
Aaron Baddeley's push to get back full playing rights on the PGA TOUR took another step forward at the Quicken Loans National tournament when he finis...
Euro Challenge Tour
Fox storms into second
A brilliant eagle at the 71st hole has catapulted New Zealand's Ryan Fox into outright second at the Challenge Tour event in Scotland this week....