Slate quarrying was an important industry for 200 years in Harford County.  Welsh settlers came to this area in the early 1700’s; the closest town, Cardiff, is named for the capitol of Wales.

The Slate Ridge quarry is the oldest slate quarry in America; the first rock quarried in 1734, but the industry did not take off until the 1800’s.  In 1848, when about 30 Welsh people arrived in Philadelphia, they traveled to Peach Bottom.  Here, they became slate quarriers, splitters, blacksmiths, and stone carvers.

The Welsh immigrants were skilled slate workmen and they found this slate easy to work with.  They operated the quarries from 1845-1860.

Rock from this quarry was used for roofing shingles, sidewalks, even tombstones.  It won first prize at the 1851 London Crystal Exposition.

Because the cost of quarrying the slate, the dangers involved, and the advent of other materials for roofing, many slate quarries were abandoned.  By 1929, only 3 Peach Bottom roofing slate operations existed in Maryland; in 1930, only 2 remained.  The slate industry declined in the 1940’s due to competition and increased cost of production.