The monument comprises an exceptionally well preserved chambered tomb of the so-called Hebridean Group, which is situated in rough grazings on the NW slope of Ben Langass, North Uist at about 45m OD.
The cairn is circular on plan, defined by a kerb of stones just over 24m in diameter. Peat has built up around the monument. A prominent landscape feature, it stands over 4m in height and is largely undisturbed, except at the E where there is a funnel-shaped forecourt which leads into a largely intact passage (about 3.5m long). At the end of the passage is a chamber which is an irregular oval on plan, measuring about 4m long by 1.8m wide, defined by large upright slabs with drystone walling above and capped by lintels.
The interior of the cairn has been partially disturbed in antiquity, although evidence survived in 1911 for 'many burnt burials' as well as unstratified finds of Neolithic and later pottery, and worked flint and mica. There is said to be a second chamber in the cairn, entered by a passage from the N.
The monument was first scheduled in 1934, but an inadequare area was included to protect all of the archaeological remains: the present scheduling rectifies this.
The area to be scheduled is circular on plan and measures 80m in diameter, centred on the cairn, to include the monument and an area around in which remains associated with its construction and use may survive, as marked in red on the accompanying map extract.