The Roseberry Homestead, also known as the Walter Gess House is a classic Georgian house, erected of rough-cut quarry stone between 1765 and 1783 in Phillipsburg, Warren County, New Jersey, United States. It is a 21⁄2-story, five-bay plan house, two rooms deep, with a center through hall. There is an attached 11⁄2-story stone kitchen, probably built before the main house. There are three chimneys—two rising from the gable ends of the main block, and the third from the gable end of the kitchen. There is a large cooking fireplace in the kitchen, with a removed brick oven. A winder stair on the fireplace wall leads to the loft above. The front of the house is on the downhill side, allowing for a walk-in cellar. There was a porch extending across the entire front, permitting access to the higher level first floor, but that has long since disappeared. John Roseberry, Sr. was one of the original settlers in Phillipsburg. It is very likely the oldest existing structure in town.
Although it is on the State and National Register of Historic Places, the Roseberry Homestead has fallen into considerable disrepair, and has been boarded up for at least 15 years. The exterior remains in relatively good condition, and the interior walls and wide board floors appear to be in safe condition. Ceilings are in much disrepair, with large areas collapsed, or the original lath showing. There are no remaining windows, and most of the doors and staircase baluster are gone. Several of the eight fireplace mantels appear to be late eighteenth century, but much of the interior woodwork is nineteenth century, and there appears to be none of the original hardware.