The 25-year old has been a superb signing for Ruaidhrí Higgins and the manager said that he was delighted to get the deal done.
"This is brilliant news for the club given Cameron's excellent form this season. He's been one of the best players in the league so far and it says a lot that he's prepared to commit to staying," explained Higgins.
"He's clearly enjoying his football here and at just 25 years of age I'm confident we're going to get his best years.
"Philip (O'Doherty, Derry City Chairman) and the Board share the same vision as us and I think it's clear that we're building a squad here that is going to be very competitive over the next few years.
"Cameron joins a number of players now on long-term contracts and I think our supporters and everyone connected with the club will be excited with the business we're doing."
"I'm really enjoying it here and the coaching staff, players and supporters have been brilliant since I joined," explained Dummigan.
"It's a great club with great people and I'm very happy here. I’ve worked with Ruaidhri for numerous years at Dundalk but this is the first year working with him as a manager an I’ve really enjoyed it.
"I like the way he wants us to play. He’s done an amazing job since he’s came in as manager. We have good players here but we know every game is difficult in this league so we’re not going to get carried away because we know every team is going to try to strengthen.
"It really is a game at a time and try to build a base that will hopefully bring success to the club."