Where most of the comparable fortifications along this stretch of water were built to accommodate six guns, the battery at Doonaha was fitted with four 24-pounders, making it the runt of a litter of artillery emplacements designed to control one of Ireland's great waterways. The iron pivot for one of the traversing gun platforms is still visible at the western end of the roof terrace, a detail easy to overlook but quietly eloquent about how these weapons were meant to swing and track a moving target on the water below.

The battery belongs to a system of fortifications built along both banks of the Shannon Estuary during the Napoleonic period, when fear of French naval incursion made the defence of Ireland's coastline a pressing concern. Paul Kerrigan, writing in 1995, placed it roughly three miles north-east of Kilcredaun Point and noted its relationship to a companion structure at Corran Point on the southern shore. The dry moat, a defensive ditch running around the landward face, has been badly eroded over the years, though it survives better here than at Corran Point. The bombproof barrack, sometimes called a defensible guardhouse, is half demolished, but what remains is instructive. These structures were built with massive barrel-vaults, curved stone ceilings designed to absorb the impact of enemy shellfire, and the vaulting here still supports what was once the gun platform above. The overall width of the battery, measured from the outer face of its flank walls, comes to around 200 feet, noticeably less than the 250-foot average of the other estuary batteries, which suggests a conscious decision to scale the installation to the particular demands of this position on the shore.