Denver's Haitzuloan — their name drawn from the Basque word for "cave" — write sludge and doom metal that genuinely sounds like something dredged from underground. Formed in 2019, they're one of the heavier entries in Denver's already formidable heavy underground.

Pasadena's Half Moon Codex operate at the intersection of sludge, drone, and doom — long-form compositions that move with the patience of tectonic plates and the weight to match. Formed in 2018, they're a fixture in the Southern California heavy underground.

Ocean Springs, Mississippi's Hallelujah Gangbang match their provocative name with sludge and doom metal dredged straight from the Gulf Coast swamp — slow, mean, and spiritually filthy since 2016.

New York's Hallux carve out a sludge/doom sound built on weight and repetition — riffs that settle in and refuse to leave, tempos that drag the listener through the muck. Formed in 2018, location unspecified, but the music speaks clearly enough.

Atlanta's Halmos have been dragging riffs through the Georgia heat since 2012, fusing the molasses weight of sludge metal with the hazy warmth of stoner grooves. Their sound sits in the slow, crushing pocket where feedback meets sweat.

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Rooted in the gritty New Haven scene, Hang Your Cross weave together hardcore aggression, crawling sludge, and the expansive textures of post-metal into a dense, suffocating sound since 2017.

Drawing equally from the murk of New Orleans sludge and the frost of black metal, Hanged Man have lurked in the Crescent City's underground since 2011, building a sound as damp and oppressive as the city itself.

Virginia's Hard Bleed formed in Woodbridge in 2026, pressing groove metal muscle into sludge metal decay — a bruising and purposefully slow-burning new entry in the Northern Virginia underground.

Evansville, Indiana's Harijin traffic in the low-and-slow heaviness of sludge and stoner metal, piling up fuzz-saturated riffs with the unhurried confidence of a band that trusts the groove. Formed in 2020, they lean hard into the hypnotic side of heavy.

California's Hat occupy a grimy corner where death metal's brutality meets sludge metal's oppressive drag, and they've been doing so since 2011. There's a caustic, tar-thick quality to their output — ugly in all the right ways.

Chicago's Hate draw from a broad well of extreme subgenres, weaving thrash, sludge, and doom into a dense, shifting sound since 2013. The Midwest backdrop gives the music a cold, industrial weight that fits the trio of genres like a rusted glove.

Minneapolis sludge and doom outfit Hatelimace wallow in the slow, corrosive weight of their craft, piling on suffocating riffs and feedback-caked heaviness that feels like the city's long winters given physical form.

Vancouver, Washington's Hauler load up on stoner and sludge metal, riding massive, distortion-soaked riffs at a pace that feels like a freight train operating at half speed — deliberate, heavy, and impossible to ignore.

New Orleans sludge/doom outfit Hawg Jaw embody the Crescent City's grimy, humidity-soaked approach to heavy music — slow, churning, and perpetually on the verge of collapse in the best possible way. Since 2009 they've been one of the Bayou scene's more viscerally satisfying acts.