It was built in 1619 by Sir Robert Newcomen in an "English manor house" style.
It was damaged during the Irish Rebellion of 1641 by Sir Phelim O' Neill and in 1689 on King James' return from the Siege of Derry.
King James ordered the Stewart Castle, and the town, to be burnt down.
An intact Bronze Age cist grave was found within castle site.
[citation needed] Newtownstewart, a plantation castle, is a State Care Historic Monument in Strabane District Council area, at grid ref: H4020 8583.