Parliamentary boundary post, McArt's Fort, Cavehill Country Park, Upper Hightown Road, Belfast, Co Antrim

A cast-iron administrative boundary post dated 1918, marking the outer extent of the jurisdiction of Belfast Corporation (as Belfast City Council was then known), and specifically marking the boundary of Duncairn District Electoral Division and Clifton Ward within it.

The post stands on the south side of McArt's Fort, just inside the ditch enclosing that scheduled monument earthwork, in an area of undulating heather moorland now part of Cavehill Country Park. It has a slightly tapered cylindrical profile with a banded octagonal base and an oversailing flat octagonal top bearing a slightly smaller fluted circular cap. The front elevation, facing east, displays a shield of Belfast Corporation's coat of arms in relief. Below this shield is the mark of a curved plaque, now missing, which was originally secured with four countersunk screws.

The post marks an invisible administrative boundary that ran along the top edge of the basalt escarpment at this location. It is situated off the main gravelled footpath around the Country Park, with a small unsurfaced path passing its west side leading up to the summit of the fort. The immediate setting is characterized by a steep drop to the east and extensive moorland to other sides.

This post was created following the Redistribution of Seats (Ireland) Act 1918, which abolished Belfast's four pre-Partition parliamentary constituencies and increased them to nine, including Duncairn. Duncairn Division encompassed the municipal ward of Duncairn and the north-east part of Clifton ward. The new constituencies were first used in the General Election of 14 December 1918, held under the Representation of the People Act 1918. This election was historically significant as the first in Britain and Ireland in which all men over 21 and all women over 30 could vote—a major expansion of the franchise from the previous property-based male-only voting system. Sir Edward Carson was the constituency's first Member of Parliament.

Following the inception of the devolved parliament for Northern Ireland in 1922, the Duncairn parliamentary constituency was abolished after just four years and the previous seat of North Belfast was restored. However, municipal wards continued to be used for local elections, though some, including Duncairn, have since been reconfigured and renamed. Belfast Corporation was superseded by Belfast City Council in 1973, with its jurisdiction extended beyond its former borough boundary. The post now lies within Cavehill District Electoral Division and within Castle Ward.

The post remains unaltered apart from the loss of its plaque and retains its original setting. It is relatively rare, as many similar posts have been lost to road widening and random removal. It possesses significant group value with a nearby boundary post on the south side of McArt's Fort and two others on the Antrim Road which also marked the same electoral division and ward boundaries. These posts, along with a number of others marking different wards elsewhere in Belfast, form the most complete group of administrative markers of this type anywhere in the province.