Included in their 20 Years of Dischord boxset is a booklet, the front cover of which features two surly young men sitting in an office overflowing with record, stickers, toys, mugs and all manner of tat. They are label founders Jeff Nelson and Ian MacKaye. The latter is sporting a shaved head and wearing shorts. On the back cover, there is a photo of the same two men, 20 years later, older and almost certainly wiser, in the same untidy office. MacKaye is still sporting a skinhead and wearing shorts.

These two images encapsulate what Dischord is about: a long-term commitment to music they believe in (and the continued wearing of shorts), an unerring dedication to document the music of their hometown, Washington DC, and a no-frills approach that is the antithesis of the boom-and-bust attitude of major labels. Which is precisely why, after nearly 30 years, it remains a touchstone of underground kudos.

Inspired by Bad Brains and the Cramps, MacKaye and Nelson formed the short-lived Teen Idles. With the $600 they earned, the pair launched Dischord in 1980, to release their single. Then they formed a new band, the pioneers of straight edge, Minor Threat. In two years Minor Threat brought a new music (hardcore) and a philosophy (a rejection of rock's excesses) to suburban America. Releases from other bands swiftly followed, including State of Alert (featuring a young Henry Rollins), Government Issue and Youth Brigade. Suddenly, Dischord was one of the key punk labels.

Living and working close to the heartland of US politics, Dischord had a philosophy from the outset: to utilise and expand the international music underground and exist independently. "In this city we had to do everything ourselves because it's basically saturated with the federal government," MacKaye told me in 2002. "The fact is, a lot of people in Washington DC don't give a damn about the government. We don't ask for their permission or guidance because they don't have a clue."

Many of the label's releases are now judged as classics of their genre, especially those from bands such as Void, Faith and Scream, who were later celebrated for launching the career of a certain 17-year-old drummer by the name of Dave Grohl – and for being the first Dischord band to be paid royalties.

Dischord's most prolific period followed 1985's "Revolution Summer", a marked attempt by MacKaye and DC's more forward-thinking artists to create an alternative to the one-dimensional hardcore scene that was now attracting violence and white power groups.

Out of Revolution Summer came Rites of Spring, Embrace, peroxide-abusers Dag Nasty, Soulside (who later became Girls Against Boys), Gray Matter – and, of course, the origin of emo. (Shortly afterwards, the key members of Rites of Spring and Minor Threat effectively joined forces to become Fugazi, one of the most important bands of the past three decades.)

More releases followed in the late 80s from Jawbox, Shudder to Think and Nation of Ulysses, a magnificently inept but sartorially dazzling band who stirred cold war references, pop culture theory and free-jazz dissonance into their brand of DC myth-making.

Though Shudder to Think and Jawbox moved away from Dischord during the alt-rock gold rush of the early 90s, the label (and MacKaye's Fugazi) turned down all offers of corporate buy-outs and stuck to their plan to release more music, this time concentrating on fellow Washington DC natives Bluetip, Circus Lupus and Make-Up.

Throughout their changing fortunes Dischord has remained a tight-knit crew, keeping their employee pool small and their overheads low. And their legacy has endured as a new generation of DC bands, such as El Guapo and Q and Not U have followed in Fugazi's footsteps.

Dischord has always been about a time and a place. And while recent years haven't been their most successful (the Minor Threat complete discography remains Dischord's biggest-selling release) you suspect a new wave of life-changing bands may still yet pass through its ranks.