Marchmont is a mile to the south of the Old Town of Edinburgh, separated from it by The Meadows and Bruntsfield Links. To the west Marchmont is bounded by Bruntsfield; to the south-southwest by Greenhill and then Morningside; to the south-southeast by The Grange; and to the east by Sciennes.

The whole area of Marchmont was a planned development, some of it being on what was previously agricultural land known as the Warrender Park - that name now being retained in such areas as Warrender Park Crescent, Warrender Park Road and Warrender Park Terrace. The name Marchmont was originally only to refer to Marchmont Crescent, Marchmont Road and Marchmont Street, but is now used for the whole area. The buildings in Marchmont are almost exclusively four-storey tenements. The earlier Victorian buildings in Marchmont are mostly pink sandstone in the form of Scottish baronial style, while the later Victorian and Edwardian buildings in Marchmont are often in blonde sandstone, and in a plainer, more regular style.

Originally, the area of Marchmont was not allowed to have any premises selling alcohol, and although that is no longer the case, there are only two notable pubs in Marchmont, The Argyle Bar and The Earl of Marchmont. There are, however, a number of off-licensed shops in Marchmont. Due to its proximity to the city centre, the presence of local amenities, and generally being considered a pleasant area, Marchmont is considered a desirable location to live in. This is reflected in higher house prices, though these are now typical of most of central Edinburgh. Marchmont is highly popular with the student population, from both Edinburgh University and Napier University which are within easy walking distance.

Streets in the Marchmont area are Arden Street, Argyle Place, Chalmers Crescent, Fingal Place, Gladstone Terrace, Lauderdale Street, Livingston Place, Mansionhouse Road, Marchmont Road, Melville Drive, Melville Terrace, Millerfield Place, Rillbank Terrace, Roseneath Place, Sciennes Road, Spottiswoode Street, Sylvan Place, Warrender Park Crescent, Warrender Park Road, Warrender Park Terrace.