Yes, it is exempt from PA state taxes.
"Pennsylvania is one of only two states to exclude virtually every type of retirement income from taxation according to Kiplinger. Public and private pensions, railroad retirement benefits and all Social Security income are excluded from taxable income for tax purposes within the state."
Source:
http://finance.zacks.com/pay-pennsylvania-tax-retired-pension-social-security-7987.html
"Pennsylvania and Mississippi are unique in that they are the only states in the country that exempt all
retirement income, even IRA, and 401(k) distributions."
Source: https://www.thebalance.com/best-states-for-retirees-3193239
