2004 . It is Mastodon's first concept album based on the 1851 novel Moby-Dick by Herman Melville. The songs "Iron Tusk," "Naked Burn," and "Blood and Thunder" were released as promotional singles, and music videos were created for "Iron Tusk," "Blood and Thunder," and "Seabeast". Three magazines awarded the album Album of the Year in 2004: Revolver, Kerrang! and Terrorizer. In 2009 and 2015 MetalSucks named Leviathan the best metal album of the 21st century.

2006 Blood Mountain is a concept album. According to bassist Troy Sanders, "It's about climbing up a mountain and the different things that can happen to you when you're stranded on a mountain, in the woods, and you're lost. You're starving, hallucinating, running into strange creatures. You're being hunted. It's about that whole struggle.

2009 Drummer Brann Dailor described the album as more "focused" than its predecessor, Blood Mountain: "Maybe there was a deeper heart to this record that needed more exploring ... We got more involved with feeling the vibe of the record and everything feels more creepy and spaced out and something special is going on.

2021 Is the first double CD for the band. There is no guest vocal from Scott Kelly of Neurosis for the first time since their 2002 debut Remission, due to Kelly's withdrawal from the music scene after admitting to domestic abuse of his wife and children. The album also serves as a tribute to Mastodon's former manager Nick John, who died from cancer in 2018. This is Mastodon's last album with founding guitarist Brent Hinds, who departed the band in March 2025.

2002 Most of the songs were written long before the album was recorded. "Trainwreck" was first performed in 2000, while vocalist Eric Saner was still in the band. "Workhorse" was premiered live in Memphis in July 2001. "Trampled Under Hoof", "Trilobite", "Where Strides the Behemoth", "Crusher Destroyer" and "Mother Puncher" were all played on a WFMU radio show on August 7, 2001. The beginning of "Crusher Destroyer" features a short sample of the roar of the Tyrannosaurus rex from the film Jurassic Park.

2017 The album was recorded at the Quarry in Kennesaw, Georgia and mixed at Henson Recording Studios in Los Angeles. The band worked with record producer Brendan O'Brien, with whom they collaborated on their 2009 album Crack the Skye. The songs were recorded as originally arranged, then they revisited each track to edit and refine the sound.

2011 The Hunter is their first release with producer Mike Elizondo. In its first week of release in the UK, the album reached number 19 on the UK Albums Chart and position number 10 on the Billboard 200 chart selling over 39,000 copies in the first week.

2014 Brann Dailor stated following about the album: "It's gonna be massive and insane, lots of epic greatness. There will be lots of huge riffs and new directions. It's real weird, real "math-y", real straightforward. It's up, down and all around.