The Montcalm Hotel (2 Wallenberg Place) and 42 Great Cumberland Place, with area railings

The Montcalm Hotel, located at 2 Wallenberg Place and incorporating 42 Great Cumberland Place, forms part of a crescent of town houses developed on the Portman Estate around 1775-1789. The development was initiated by Abraham Adams and completed by William Porden. Originally five separate houses, the northernmost property at 42 Great Cumberland Place was rebuilt in the 1950s, while the remaining four have been redeveloped as a hotel behind their original facades.

The town houses are constructed of stock brick with stucco banding to the ground floors. The four southern houses have 20th-century dormered mansard roofs, later altered to flat roofs at the rear. Number 42 Great Cumberland Place has a flat roof. Brick stacks are present. Most of the window openings on the front elevation retain sash frames, some of which are likely original.

The buildings follow a crescent shape, with the street frontage facing Wallenberg Place and number 42 Great Cumberland Place marking the corner with Upper Berkeley Street.

The principal facade facing Wallenberg Place presents a uniform appearance: each house is three windows wide, arranged over three original storeys and a basement, with a later attic storey above the cornice. Each house originally featured a semicircular-arched doorway within the southern bay, flanked by narrow pilasters, with a reeded frieze below a fanlight to illuminate a six-panelled door. Some doorways have been altered; a mid-19th century Doric portico exists at the former number 39, and a later architrave replaces the original at the former number 41. Windows are set within flat, gauged arches. A platband defines the termination of the ground-floor stucco, and a stucco entablature sits above the second floor, with a secondary cornice and blocking course marking the later attic storey. Delicate semicircular balconies originally adorned most first-floor windows, with later cast-iron balconies added to the former numbers 36 and 38.

The west elevation, along Great Cumberland Place, and the north elevation, facing Upper Berkeley Street, of the rebuilt number 42, are similarly detailed, although without doorways or balconies. The north elevation of the former number 40 on Upper Berkeley Street retains balconies. A 1957 photograph reveals that the building was originally three storeys high, but has since been raised to four storeys to match the rest of the crescent. The eastern ground-floor window has also been converted into a door opening.

The east elevation of the four southern houses has been rebuilt following the curve of the crescent in a stepped plan.

The interiors of the historic houses have been completely or almost completely rebuilt behind the original street facade.

The buildings are accompanied by cast-iron area railings with spearhead finials.