Nothing now remains of Athelstaneford Castle itself, although a solitary doocot hints at what once stood nearby.
The doocot is said to have been built in 1583 by George Hepburn, but Athelstaneford Castle predated that.

Hendrik Hondius, Amsterdam, 1630map image courtesy of NLS
Athelstaneford Castle may have been destroyed by Oliver Cromwell following his victory at the Battle of Dunbar in 1650 when he is known to have sacked Dirleton Castle, Hailes Castle, Innerwick Castle, and Tantallon Castle.

Joan Blaeu, Amsterdam, 1654map image courtesy of NLS
In 1655 the lands were bought by Sir Francis Kinloch along with the estates of Gilmerton and Markle.

John Adair, 1682map image courtesy of NLS
In 1851 Athelstaneford Castle was still standing and was described as “a plain old edifice, situated at the east end of the village burying-ground, and not many yards from the foundation of a ruined church” and “stands about a hundred paces back from the main-street of the hamlet, and is principally distinguished by a great projecting chimney or ingle lum. It consists of two stories, and occupies a prominent situation on rising ground.”
This would seem to place it to the rear of the plot on which Oaklea cottage now stands. A substantial house aligned east to west is shown on the Ordnance Survey map of 1894 to the east of the church but isn’t shown on the 1907 map.

Ordnance Survey, 1894map image courtesy of NLS
Alternative names for Athelstaneford Castle
Athelstan foord; Athelstaneford House; Athelstanfoord; Athelstonefoord; Athelstonford; Athelstounford; Atholstonsford; Ethilstanefurd