Devices having gate-to-gate isolation structures and methods of manufacture are provided. The method includes forming a plurality of isolation structures in a pad film and an underlying substrate. The method further includes protecting at least one of the plurality of isolation structures in order to preserve its height. The method further includes removing portions of unprotected isolation structures such that the unprotected isolation structures are of a different height than the at least one of the plurality isolation structures. The method further includes removing the pad film and protection over the at least one of the plurality isolation structures, wherein the at least one of the plurality of isolation structures extends above the underlying substrate. The method further includes forming at least one gate electrode on the substrate, over the remaining isolation structures and abutting sides of the at least one of the plurality of isolation structures.