2026 fiscal calendar
Know the tax date before it becomes a penalty date.
Tax bills, payment rules, and valuation-review windows are controlled by the local jurisdiction and the governing state framework. The verified record below separates published figures from dates that require confirmation with Mercer County Tax Assessment Office.
Effective rate
county, municipal, and school millage varies by taxing district; no single countywide effective average is published.
Statement mailing
current-year taxes are administered by local district collectors and official Mercer County sources reviewed do not publish one countywide 2026 bill-mailing date.
Payment deadline
Current-year real-estate taxes are paid to local district collectors; official Mercer County Tax Claim states 2026 taxes not paid in full by December 31 become delinquent, unpaid claims are returned by January 15, and 9% interest begins in February. 2026 upset tax sale dates for prior-year delinquency are September 15 and October 20, 2026.
Valuation protest
September 1, 2026 by 4:30 p.m. for assessment appeals; 2026 filing fees are waived until September 1, and change/reassessment notices, if issued, control.
Critical payment warning
Do not assume a grace period.
The verified county record identifies the payment timing above but does not establish a universal penalty schedule for this page. Late charges, interest, collection costs, tax-sale procedures, and lien or foreclosure timelines can depend on state law and the local collector’s process. If the deadline is close or a balance is delinquent, contact the tax collector directly and request the current payoff amount in writing.
Treat the published payment deadline as a hard operational date and retain your receipt or confirmation number.
Read the calendar in order
From assessment to collection
1. Valuation and notice
Review the assessment notice as soon as it arrives. The protest window may run from the notice date rather than from the payment due date.
2. Statement and account review
Match the tax statement to the parcel or account number and confirm exemptions, assessed value, taxing units, credits, and balance.
3. Payment confirmation
Use the official collector channel, then save the receipt, transaction reference, and date posted. A bank submission is not always the same as a county posting date.