Pennsylvania 2018 Important Dates to Remember (73.7 KiB) are key dates for Pennsylvania residents, businesses, and organizations to be aware of for the upcoming calendar year. These dates include primary elections, general elections, registration deadlines, tax deadlines, and other important state and federal deadlines. The key dates are divided into two categories: Primary Elections: — March 6th: Last Day to Register to Vote in the Primary — April 24th: Primary Election Day General Elections: — October 9th: Last Day to Register to Vote in the General Election — November 6th: General Election Day Registration Deadlines: — April 16th: Deadline to Register to Vote in the Primary — October 9th: Deadline to Register to Vote in the General Election Tax Deadlines: — April 17th: Deadline for 2017 Personal Income Tax Returns — April 17th: Deadline for 2017 Business Tax Returns — October 15th: Deadline for 2018 Personal Income Tax Returns — October 15th: Deadline for 2018 Business Tax Returns Other Important Dates: — April 1st: Deadline for Property Tax/Rent Rebate Program — April 1st: Deadline for 2017 Homestead and Farmstead Exclusion — November 1st: Deadline for 2018 Homestead and Farmstead Exclusion.