Summer Siege was the Canton of Harrowgate Heath's yearly melee event. Also found was thrown-weapons tournaments, archery tournaments, fencing, and an A&S competition.

The event lives on even though Harrowgate Heath has passed into memory.

Championship Tournaments for archery and thrown weapons are historically held at Summer Siege. Of course, this is at the whim of Their Excellencies.

Summer Siege focuses on melee fighting, though the scenarios change annually. Past themes have included a castle siege battle and boat wars. Starting in AS XLVI a 'peasant battle' was added where the attending populace could throw 'rocks' at the fighters as they fought; this proved quite popular and will most likely be a recurring battle.

Originally held at Michael Eastbrooke's farm, Summer Siege then spent a couple of years at the Chesterville Fair Grounds and another couple at John Wood's farm in Kemptville. Starting in 2015 it has been held at the Maple Ridge Center in CHesterville, ON.

Usually held at the end of August, post-Pennsic.