In 1903, Hershey began construction of a chocolate plant in his hometown, Derry Church, Pennsylvania, which later came to be known as Hershey, Pennsylvania.[5] The town was an inexpensive place for the workers and their families to live. In 1907, Hershey introduced a new candy, small flat-bottomed conical-shaped pieces of chocolate that he named "Hershey's Kiss". Initially they were individually wrapped by hand in squares of foil, and the introduction of machine wrapping in 1921 simplified the process while adding the small paper ribbon to the top of the package to indicate that it was a genuine Hershey product.

The first plant outside Hershey, Pennsylvania opened on June 15, 1963 in Smiths Falls, Ontario, Canada and the third opened on May 22, 1965 in Oakdale, California.In February and April 2007 Hershey's announced that their Smiths Falls and Oakdal plants would close in 2008, being replaced in part by a new facility in Monterrey, Mexico. The Oakdale factory closed on February 1, 2008. Hershey chocolate factory in São Roque, Brazil was opened in August 2002.