Ewloe Castle (Welsh: Castell Ewlo) is a native Welsh castle near the town of Ewloe in Flintshire, Wales. The castle, which was one of the last fortifications to be built by the sovereign Princes of Wales, was abandoned at the beginning of the invasion of Wales by Edward I in 1277. Its construction, using locally quarried sandstone, appears to have continued piecemeal over many years and may have not been completed.