Aikwood Tower (also known as Oakwood Tower) is a 16th-century tower house in the Scottish Borders area of Scotland, 4 mi southwest of the town of Selkirk, on the Ettrick Water.
 The tower is a Category A listed building.
Newtown Castle is a 16th-century tower house, located close to the village of Ballyvaughan within the Burren area of County Clare, Ireland.
 Uniquely for a tower house of its type in Ireland, Newtown Castle is mostly cylindrical in shape but rises from a square pyramidical base.
 It is today part of the Burren College of Art.
Moniack Castle is a 16th-century tower house located 7 mi west of Inverness, and just south of Beauly in Highland, Scotland.
 The castle was built in 1580 by members of the Clan Fraser.
 The castle is protected as a category B listed building.
Repentance Tower is a 16th-century tower house situated near Annan, Dumfries and Galloway.
 Built in 1565 by John Maxwell, it served as a watchtower for Hoddom Castle.
 The tower takes its name from an inscription above the door.
Fordell Castle is a restored 16th-century tower house, located 1.25 mi north-west of Dalgety Bay and 2 mi east of Dunfermline, in Fife, Scotland.
Quoile Castle is a castle situated 1.5 miles (2.4km) from Downpatrick, County Down, Northern Ireland, just off the main road from Downpatrick to Strangford, on the east bank of the River Quoile.
 It is a 16th-century tower house, which was inhabited into the 18th century.
 Quoile Castle tower house is a State Care Historic Monument in the townland of Quoile, in Down District Council area, at grid ref: J4963 4701.
Gilnockie Tower is a 16th-century tower house, located at the hamlet of Hollows, 2.3 km north of Canonbie, in Dumfries and Galloway, south-west Scotland.
 The tower is situated on the west bank of the River Esk.
 It was originally known as Hollows Tower.
 Gilnockie Castle is a separate, but nearby site.
Greenknowe Tower is a 16th-century tower house, located just west of the village of Gordon, in the Scottish Borders.
 Although a roofless ruin, the stonework of the tower is well preserved, and represents a fine example of a later tower house, built more as a residence rather than as a place of defence.
 The building is located at [ NT639428] , beside the A6105 road.
 It is a Scheduled Ancient Monument, and is in the care of Historic Scotland.
The Tower of Hallbar, also known as Hallbar Tower and Braidwood Castle, is a 16th-century tower house, located to the west of the River Clyde in South Lanarkshire, Scotland.
 The tower is situated above the Fiddler Burn, 3.5 km south-west of Carluke, and 1.5 km east of Crossford.
 It has recently been restored and is let out as holiday accommodation.
The Clan Henderson (Clann Eanruig) is a Scottish clan.
 The clan's historical seat is at Fordell Castle in Dalgety Bay, Fife.
 The current clan chief is Alistair Henderson of Fordell.

Question: Clan Henderson has a historical seat at what 16th-century tower house?
Answer: Fordell Castle