The bridge designs comprise a semi-circular, single-span bridge, which, when executed, was 70 feet long and 42 feet in height. The elevation of the bridge (SM 34/110) contains three variant designs on one drawing. Each variant has rusticated piers, voussoirs, a panel frieze, wall parapet and the Buccleuch crest (a stag) in the centre of the parapet. One variant has plain piers, one with urn-filled niches and a panel containing strigillation above, and one with pedimented niches with Greek Doric columns, arabesque panels and reclining figures at each end of the parapet, exhibiting Adam’s use of the quasi-Greek Doric order. The simpler design (with niches and strigillated panels) was executed without the rusticated piers or voussoirs, owing to its construction in ashlar. It is not clear if the stag was ever constructed. The bridge was later named, ‘Montagu Bridge’ and is listed Category A on the Scotland Register.

There is a coloured perspective of the bridge similar to SM Adam volume 2/181, at the Scottish National Gallery. The drawing is signed by Robert Adam and dated 1791 and would suggest that the other drawings showing the same or variant design likely date from the same year. The drawing also appears to have scars from fliers suggesting this perspective also contained variant designs for the piers. There is another watercolour perspective of the bridge, attributed to Robert Adam, at the Buccleuch archives.