According to HISGEN Register, 1941, v 95, p 165: Benjamin Gilbert Follansbee b. 15 May 1851 Pittsburgh of Gilbert & Maria Jackson (Haynes) Follansbee, d. 10 May 1939 Pittsburgh; m. 6 Oct 1887 Frances S. Wright. Gilbert b. 5 Jan 1821 Plaistow NH, d. 15 May 1917 Pittsburgh.Gilbert's father John Follansbee (in War of 1812), m. Elizabeth Haynes and moved to Pittsburgh.In 1894 Benjamin organized Follansbee Brothers Co., opened a plant in Follansbee WV in 1902.
Follansbee WV was named sometime after 1902, so I would assume it was named for the company or for Benjamin.