The Summer Slaughter Tour

The Summer Slaughter Tour is an annual heavy metal music tour held every year since 2007. It originated in North America in 2007 and has toured in Canada in 2008, Europe in 2008, and Australia and New Zealand in 2009. Billed as "The Most Extreme Tour of the Year", Summer Slaughter has earned a reputation as being one of the few summer tours to cater exclusively to fans of extreme forms of metal music. Starting in 2012, Summer Slaughter began to add more progressive metal bands to their lineups, seeing Between the Buried and Me co-headline with Cannibal Corpse. Periphery also played Summer Slaughter 2012, and came back during Summer Slaughter 2013, along with progressive metal bands Animals as Leaders and The Ocean. The focus on progressive metal that year was controversial and many people were "into" heavy metal music, and death metal focused lineups returned in 2014, seeing Morbid Angel headline.
2007.
Headliner:
Supporting bands:
Tour dates
2008.
Headliner:
Supporting bands:
Tour dates:
2008 (Canada).
Headliner:
Support bands:
Tour dates
2008 (Europe).
Headliner:
Supporting bands:
Tour dates
2009 (Australia/New Zealand).
Headliner:
Supporting bands:
Tour dates
2009.
Headliners:
Supporting bands:
Tour dates:
2010.
Headliner:
Supporting bands:
Tour dates:
2010 (Mexico).
Headliners
Support bands
Tour dates
2011.
Headliners: 
Supporting bands:
Tour dates: 
2012.
Headliners: 
Supporting bands:
Tour dates
2013.
Headliner:
Supporting bands:
Tour dates:
2014.
Headliner:
Supporting bands:
Tour dates:
2014 (Canada).
Headliner:
Supporting bands:
Tour dates:
2015.
Headliner:
Supporting bands:
Obscura and After the Burial were originally scheduled to appear on the tour. Obscura dropped off due to visa issues and After the Burial dropped off due to the death of their guitarist Justin Lowe.
Tour dates: 
2016.
Headliner:
Supporting bands:
2017.
Headliners:
Supporting bands:
The Black Dahlia Murder will play their 2007 album "Nocturnal" in its entirety for their 10th anniversary. 
AngelMaker was voted in by fans during the Summer Slaughter Poll.
Slaughter to Prevail travel plans were delayed and they couldn't make the tour.
2018.
Headliner:
Supporting bands:
Soreption only played a few tour dates and then dropped off due to unforeseen circumstances.
2019.
Co-Headliners
Support bands:
The Slaughter Survivors Tour 2011 (North America).
Headliner:
Support bands:
Tour dates
The Slaughter Survivors Tour 2012 (North America).
Headliner:
Support bands:
Tour dates
Fan-voted openers.
In 2011, the Summer Slaughter Tour offered their fans the opportunity to vote on who would open the tour. The choices for 2011 were Dawn of Ashes, Revocation, Neuraxis, Conducting From The Grave, The Contortionist, Within The Ruins, Volumes, Augury, 7 Horns 7 Eyes, Rings of Saturn, and Struc/tures. Within the Ruins ultimately received the most votes and thus won the opening spot for the tour. That same year Conducting From The Grave, The Contortionist, Rings of Saturn, Volumes, and Struc/tures all toured together on what was billed as the Slaughter Survivors Tour. This tour also included Scale the Summit, who had not been part of the voting.
For the 2012 edition of the Summer Slaughter Tour, fans were once again given the chance to vote on the opening act. The choices for 2012 were Aegaeon, Battlecross, Cerebral Bore, Enfold Darkness, Fallujah, Fit for an Autopsy, Hour of Penance, I Declare War, Pathology, and Vildhjarta. The opening slot for the 2012 tour went to Cerebral Bore, and Pathology, Enfold Darkness, Fallujah, Fit for an Autopsy, and Aegaeon also joined the 2012 Slaughter Survivors Tour.
The choices for the 2013 tour were Abiotic, As They Burn, Dark Sermon, Erra, Fit for an Autopsy, Howl, Intervals, Into the Flood, King Conquer, Last Chance To Reason, My Bitter End, Nekrogoblikon, Rings of Saturn, Syqem, Soreption, Today I Caught the Plague, and Thy Art Is Murder. Thy Art Is Murder was the chosen band. However, since they were nearly tied with Rings of Saturn by a few votes, the organizers decided to put both Rings of Saturn and Thy Art Is Murder on the bill. Vektor were put on the initial ballot by their record label without the band's knowledge or approval, and upon discovering this, had to withdraw due to incompatible scheduling. The Slaughter Survivors Tour didn't occur in 2013, and didn't return in 2014 either.
Summer Slaughter 2014 didn't see the tour offer an opportunity to vote on openers; rather, the opener was chosen by Headbang for the Highway showcase, and Boreworm was selected. Mayhem Festival also uses the Headbang for the Highway showcase to select bands.