In response to questions regarding prepayment of 2018 property taxes in the 2017 calendar year, please see the Executive Order issued by Governor Christie requiring municipalities to accept tax prepayments if postmarked or delivered on or before Dec. 31, 2017.

Here is an article that you might find of interest. Right now it looks like you can deduct tax pre-payment made by 12/31/17 on your 2017 taxes, but there are some concerns voiced as to whether or not that will help you. As always, consult your accountant or tax advisor.
The Borough is currently accepting pre-payment of property taxes. Payments may be made online. Follow the ‘online payments’ link on the Borough’s website.
Or, taxes can be mailed or delivered to Chester Borough Hall 50 North Road Chester, NJ 07930.