Created on March 22, 1820, from part of Cumberland County and named in honor of Oliver Hazard Perry, victor in the Battle of Lake Erie. Bloomfield, the county seat after 1827, bears the name given to the tract of land in the original patent. It is said that it was laid out in the month of June 1822, when clover was in bloom. It was incorporated as a borough on March 14, 1831. The post office name for Bloomfield is New Bloomfield.

     The area was a favorite for illegal squatters before Indians yielded the land at the Treaty of Albany in 1754. Sherman’s Valley was the scene of Indian attacks in 1755 and 1756. The county was formed in order to eliminate trips to Carlisle. In 1820 Sherman’s Valley boasted forty-eight grist and merchant mills, a forge, ten fulling mills, sixty sawmills, eight carding machines, four oil mills, a furnace, two tilted hammers, and a powder mill. Waterpower was king. The Pennsylvania Canal had four locks in Perry; the economies of Duncannon, New Buffalo, Liverpool, and Newport depended on the canal from 1828 to 1901, when it was closed. Perry also had the Juniata Canal from 1828 to 1898. The county made high-quality hickory barrel hoops. Lumbering continues today, serving over a dozen active sawmills. Farms occupy 32 percent of the land. Retail sales have been low in the last two decades due to convenient shopping center beyond the county lines. Home building has been strong since 1970. Almost two-thirds of the resident population work force is employed outside the county.