For a long time, if you wanted to camp in the Ontario Parks backcountry, you had to call the Ontario Parks Reservation line and talk to an agent. Well, not anymore! Now you can book Algonquin and Killarney Interior campsites online.
Initially only selected parks had online reservations for backcountry, including the two newer ones, Massasauga and Kawartha Highlands, and the smaller ones like Bon Echo, Charleston Lake and Frontenac. All of these parks offered reservations by numbered site. You had to choose a particular site to be able to stay there. They added pictures to a lot of these sites so you could see what you were booking.
As of March 2015, the backcountry lakes in Killarney and Algonquin are also available through the online reservation system. The earliest you can book your trip through the system is Friday April 24, 2015. In Algonquin and Killarney, the reservation system is booked by lakes not specific sites, and each site is called a tent pad. You can book both canoe sites, and backpacking trail sites (though not the Killarney La Cloche Silhouette Trail). Quetico is also available but it wasn’t working for me when I tried.