An integrated circuit device includes a conductive region disposed on a substrate, an insulating structure including a contact hole disposed in the conductive region and extending from the conductive region in a vertical direction, a local capping pattern having an outer sidewall in contact with an upper portion of an inner wall of the contact hole and an inner sidewall facing an inside of the contact hole and having a width gradually increasing in a horizontal direction away from the substrate, and a conductive plug passing through the insulating structure through the contact hole in the vertical direction, having a lower sidewall in contact with the insulating structure and an upper sidewall in contact with the local capping pattern, and including a first metal.