A method for making a semiconductor device may include forming first and second spaced apart semiconductor active regions with an insulating region therebetween, forming at least one sacrificial gate line extending between the first and second spaced apart semiconductor active regions and over the insulating region, and forming sidewall spacers on opposing sides of the at least one sacrificial gate line. The method may further include removing portions of the at least one sacrificial gate line within the sidewall spacers and above the insulating region defining at least one gate line end recess, filling the at least one gate line end recess with a dielectric material, and forming respective replacement gates in place of portions of the at least one sacrificial gate line above the first and second spaced apart semiconductor active regions.