Trovinger Mill is constructed of roughly coursed local fieldstone. It is five bays in length with the mill race running underneath it about midway along its broad side. At the peak of the east gable is a date stone marked 1771 with the initials "J.R." The stonework at the exterior of the building shows a number of seams in the walls probably indicating several periods of building. A vertical division line in the stone is evident just west of the mill race. A horizontal seam in the masonry is evident about eight feet above ground level, running along north, west, and south walls west of the race. Within this area there is evidence that window openings in the north and south walls have been raised about one foot. Most of the windows and doors in the east, north, and west walls of the building are topped with segmental arches. The openings in the north and south walls for the race are lined with coursed upright stones forming a segmental arch. Many early timbers and milling machinery can be observed in the race. The ends of the roof at the gables are finished with a tapered barge board. The roof extends beyond the north wall of the building several feet to cover the remains of an elevated walkway which gives access to the second story openings. The roof covering is sheet metal, under which can be seen earlier wooden shingles. Two small gabled dormers are present on the south side of the roof. The mill race remains intact with concrete side walls near the building. Nearby is the site of a new mill which is said to date later than the grain mill. Also present are the abutments of a bridge which crossed the Antietam at the mill as part of an 18th century road leading from Hagerstown to the Old Forge about 1 1/2 miles upstream.
The Trovinger Mill, originally Jacob Rohrer's Mill, is significant for its architecture and for its contribution to early commerce in Washington County. A dated example of Washington County's 18th century architecture, the mill has received few significant alterations since 1771. Much of the original woodwork remains as well as a significant part of the milling machinery. Functioning as an early business, the mill represents an important part of the early economy of Western Maryland. A large number of mills were in operation along the Antietam Creek during the 18th century (at least ten are shown on a 1794 map), an indication that milling was a major industry in the area. Unfortunately, few of these mills are standing today. There is considerable evidence to suggest that Jacob Rohrer's establishment was among the earliest of the mills on the Antietam. The seams in the masonry of the building indicate that an earlier one-story structure may have been present before 1771. The physical evidence of an earlier mill is supported by documentary references in patent records of Frederick County. The mill was in the Rohrer family until 1817. The Trovingers who operated the mill from 1875 to 1910 contributed only the present name of the structure to its history. It continued functioning as a grist mill into the 20th century.
Though the mill has not operated for more than a century the building appears to be in a well maintained condition and appears to be used for other purposes for the residence that is located adjacent to the mill.