4 Finsbury Square

4 Finsbury Square is a two-storey building with a cellar, featuring one window and a canted back from the line of the terrace at the center of the front elevation. The exterior is made of coursed rubble masonry, topped with a moderately pitched slate roof that includes an iron skylight and plain close eaves. The stone stacks have simply moulded caps and water tabling.

On the upper floor, there is a shallow Victorian sash window set under the eaves. The ground floor has a similar but larger window, which is set beneath a stone lintel. The cellar opening is offset to the left and features a cambered arch cut into the stone lintel.

The doorway is positioned to the left, beyond the angle where the front cants back, and is topped with a stone lintel. It includes a shallow two-light rectangular fanlight, a modern door, and slate treads.