This octagonal tower near Keenagh in County Longford is a little different: the house it served is gone entirely, demolished and reduced to a site, while the dovecote that once supplied its table with squabs and eggs still stands three storeys tall in the grounds of Mosstown Demesne. A dovecote, sometimes called a pigeon house, was a standard fixture of a prosperous eighteenth-century Irish estate, providing a reliable source of fresh meat and fertiliser. What is less common is one of this scale and architectural ambition surviving more or less intact while the main house has vanished.

Built around 1750 and associated with the now-demolished Mosstown House, the building is a considered piece of work for what was essentially a functional outbuilding. Its octagonal plan rises through three storeys beneath a hipped artificial slate roof of matching octagonal profile, topped by a lantern with a metal weather vane. The walls are roughcast rendered over roughly coursed limestone, with raised block-and-start quoins at the corners and a string course marking the division above the ground floor. The upper floors have blind openings, meaning they are recessed into the wall surface but sealed rather than glazed or open, a detail that gives the building a slightly sealed, self-contained quality from the outside. Inside, the ground floor retains a domed brick ceiling, a small but striking detail that suggests the builder was thinking about more than bare utility. Voussoirs, the wedge-shaped stones that form an arch, are visible at the ground floor openings where the render has thinned, offering a glimpse of the limestone structure beneath the surface finish.