If you are conducting research in the Western, Maryland vicinity and in particular Frederick, be sure to visit the Historical Society of Frederick. According to their website the Society was founded in 1892 and later incorporated in 1911. The facility is well managed and the staff and volunteers are most helpful. Current events, hours and directions can be found on their website and by clicking the hyperlink provided above.
To aid you in preparation for your visit the Society you may want to check out their online catalog – ARCHIVES & RESEARCH CENTER CATALOG. Happy hunting and let me know if you ever need assistance.