Catoctin Furnace is a group of archaeological sites associated with a 10,000-acre iron working furnace complex dating from the late 18th and 19th centuries in Frederick County, Maryland. The collection includes materials from the foundry site (18FR320), a springhouse site (18FR321), an African-American slave cemetery (18FR323), and a 19th-century miner’s house (18FR324). These sites were documented in 1977 during a Phase I survey by Orr and Son for the proposed dualization of U.S. Route 15 between Putnam Road and Maryland Route 77 in Thurmont. Catoctin Furnace represents a valuable resource for documenting the development of the iron industry in the United States and increasing understanding about the lifestyles and material culture of its workers.

Catoctin Furnace Bathhouse/Springhouse/Raceway (18FR321)

The Catoctin Furnace Bathhouse/Springhouse/Raceway Site (18FR321) is a 19th-century structure associated with a spring near the Auburn Mansion. The stone building was utilized as a springhouse from approximately 1815 to 1860, when it was modified to a bathhouse. A raceway was later constructed to channel water to Auburn Pond.

The earliest structure at 18FR321 had a mortarless fieldstone foundation measuring 12 feet on each side, and a brick entry step, and appeared to function as a springhouse for the refrigeration of foods. A one-inch thick wooden trough was placed around the interior of the stone walls to channel spring water into a metal catch basin in the southeast corner. Orr and Orr conjectured that a raised brick floor was present in the structure’s unexcavated center. Water escaped through a barred grill on the downhill side, which continued in use after renovations converted the building into a bathhouse. A foot of soil was placed over the original floor, and a "Y"-shaped brick drain was used to transport water directly to the square iron catch basin, from which a pipe was installed to channel water outside of the structure. A new flagstone floor was put down, and a bathtub was installed in the southwest corner, where a square pipe was located. A photograph revealed that the building was plastered, and had a shingled roof. The building was abandoned in 1915, when indoor plumbing was installed in the Auburn Mansion, and its fieldstone walls were later used to construct a driveway.

Archaeological Investigations

During the Phase I survey in 1977, Orr and Son excavated one two-by-two-foot test unit in the northwest corner of the building, revealing six courses of fieldstone three feet below the ground surface. An additional two-by-two-foot test unit was placed in the structure’s interior, uncovering a stone floor at a depth of 18 inches. Orr and Son also conducted Phase II investigations at 18FR321 in 1979. Four trenches were excavated to subsoil at the corners of the building, perpendicular to the walls, and were expanded to explore up to half of each wall. In addition, two pathway trenches were dug, one in front of the doorway and one eight feet east of the southeast corner. Stratigraphic layers were excavated separately, and all soil was screened through 1/8-inch mesh. The Phase II investigation excavated approximately 50% of the site before it was buried for the dualization of U.S. Route 15.


A total of 7,815 artifacts were recovered during the investigations at the Catoctin Furnace Springhouse/Bathhouse/Raceway Site. Artifact analysis was used primarily to date specific renovations to the structure and to define the activities that occurred at the site.

Artifacts date the construction of the springhouse to the early 19th century, and included items which are considered to be functionally related to its activities. Four hundred and fifty ceramic sherds, dating from c.1820-c.1860, include American stoneware and earthenware vessels, and a large amount of transfer-printed and blue and green shell-edged pearlwares and whitewares. The majority of the ceramic sherds are kitchen-related wares representing dishes and crocks for food storage and refrigeration. Architectural debris, such as nails, plaster, and brick fragments, were also common.

The conversion to a bathhouse is evident in the artifacts dating from the second half of the 19th century. Sixteen complete bricks and a large number of hand-molded brick fragments were discovered in the fill that elevated the stone floor. Other architectural debris included flagstone spalls, nails, mortar, and plaster. Ceramics and glass bottle fragments also dated from the late 19th century.


The Catoctin Furnace Records Collection has been divided into four areas by archaeological site number: the Foundry (18FR320); the Springhouse/Bathhouse/Raceway (18FR321); the Renner Burials (18FR323); and the Carty House (18FR324). Original records for all four sites are minimal, but those that exist are in good condition, with little dirt and staining. The collection is composed of four letter-sized archival clamshells, one oversized enclosure, and one document roll.

Excavation records for 18FR320 consist of daily field journals, plans, and profiles. They have been organized by year of excavation (1979 and 1981). For the 1979 excavations, only nine feature forms are present. All other records have been scanned as .PDF files, available online but not searchable. They include plans/profiles, bag and photograph logs, background research, elevation/depth records, notes on the basin dam, oversized maps, and other miscellany. There are two reports on the Foundry site: Archaeological Excavations at Site 18FR320 Catoctin, Maryland (Milner 1979), and A Report on the Excavation of an Ancillary Area (Site 18FR320) of the Historic Ironworking Complex at Catoctin Furnace, Frederick County, MD (Parrington and Schenck 1982). All type-written reports are available online in .PDF format and are word searchable.

Excavation records for 18FR321 are incomplete and have not been included in the database. All records have been scanned as .PDF files and are not searchable. They include plans/profiles, elevations, artifact catalogue packing and delivery lists, ceramic analysis, miscellaneous artifact analysis, geological reports, and miscellaneous maps. Two reports for the Springhouse/Bathhouse/Raceway are included: Interim Report of the Catoctin Furnace Archaeological Mitigation Project (Orr and Orr 1980); and The Catoctin Furnace Archaeological Mitigation Project Final Report of the 1979 Excavation (first, second, and final drafts) (Orr 1982).

There are no excavation records for 18FR323 (Renner Burials) and 18FR324 (Carty House). A small number of miscellaneous notes have been scanned as a single .PDF file. One report exists: Archaeological Data Recovery at Catoctin Furnace Cemetery (Burnston and Thomas 1981).

Photographs taken on-site or in post-processing are available through the online database, and are searchable using the above criteria. Researchers should note that images are not linked directly to specific documents, and photographic records do not necessarily exist for all features or units. Original images consist of slides, negatives, contact sheets, and prints, and are housed at the MAC Lab.


Burnston, Sharon A. and Ronald A. Thomas
1981     Archaeological Data Recovery at Catoctin Furnace Cemetery, Frederick County, Maryland. Report prepared for the Maryland Department of Transportation by Mid-Atlantic Research, Newark, DE.
John Milner Associates
1980     Archeological Excavations at Site 18FR320, Catoctin, Maryland. Manuscript on file at the Maryland Archaeological Conservation Laboratory.
Orr, Kenneth G. and Ronald G. Orr
1980     Interim Report of the Catoctin Furnace Archaeological Mitigation Project, Contract F522-152-770. Report prepared for the Maryland State Highway Administration.
1977     An Intensive Archaeological Survey of Alignment 1 Corridor, U.S. Route 15 from Putnam Road to Maryland Route 77 in Frederick County, Maryland. Report prepared for the Maryland Department of Transportation.
Parrington, Michael and Helen Schenck
1980     A Report on the Excavation of an Ancillary Area (Site 18FR320) of the Historic Ironworking Complex at Catoctin Furnace, Frederick County, Maryland. Report prepared for the Maryland State Highway Administration by John Milner Associates, West Chester, PA.

Digital Resources


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An online archive of over 30 archaeological sites in Maryland, produced by the Maryland Archaeological Conservation Lab with the support of the National Endowment of the Humanities.