Throughout the 19th century, textiles production continued in the county. Fulling and woolen mills continued, while cotton production slowed down. As the century progressed, a new facet of the industry took hold: the manufacturing of clothing. Sewing factories opened throughout the county, producing everything from shirts to suits to seamless hosiery.
In 1887 five Frederick men chartered the Frederick Seamless Hosiery Company, making half-hose for men, with 18 knitting machines and 15 female employees. The factory was located at 34-36 East Patrick Street, but later moved to the Vulcan Iron Works building at 340 East Patrick Street. In 1889 it was renamed the Union Manufacturing Company. After the Dupont Company invented nylon, they challenged the Union Manufacturing Company to try to make hosiery with nylon.
After experimenting for several days, they succeeded and produced the first seamless nylon hosiery in 1937.