Find the county first, then search its official portal by address, owner, or parcel number.
A homestead exemption, senior-relief program, or valuation protest can change the amount a homeowner owes—but only if the filing reaches the right local office in the correct window. Use the reviewed county guidance below as your working checklist, then confirm the current form and deadline with Mercer County Auditor (Jeffrey S. Larmore) / Mercer County Treasurer.
The filing guidance for this county is: December 31, 2026 for a 2026 real-property homestead application; file with the county Auditor under Ohio's DTE 105A schedule. Use the official form or application channel, provide the residence and ownership documentation requested, and keep a copy of the submission.
Open homestead application (opens in a new tab)Mercer County states the Ohio homestead exemption is available to homeowners age 65+ and permanently and totally disabled homeowners, subject to the income means test. For tax year 2025 collected in 2026, qualifying applicants generally may shield up to $29,000 of market value; the county also provides the DTE 105A application and disabled-veteran forms.
No general county parcel-value cap was published. Ohio assesses real property at 35% of market value, reappraises every six years with triennial updates, and applies HB 920 reduction factors and the 10-mill limitation. House Bill 186, effective March 20, 2026, creates an automatic Inflation Cap Credit for qualifying school-district/JVS levy growth; it is a tax credit/collection limitation, not a general cap on appraised or taxable parcel value.
Use the valuation notice and the county’s published protest guidance to determine the last day to file. Do not assume the payment deadline controls the appeal.
Gather comparable sales, photographs, repair records, appraisal evidence, property characteristics, and any documentation that explains why the assessed value is incorrect.
Submit through the official channel, save the confirmation, and attend the board or review hearing if one is scheduled. An appraiser or attorney can help evaluate evidence when the value or stakes are substantial.
The reviewed protest guidance for this county is: January 1–March 31, 2027 for 2026 valuation complaints; Mercer County states complaints for tax year 2026 may be submitted during that period. For the 2025 tax year payable in 2026, the prior window was January 1–March 31, 2026. If the language is not a specific calendar date, contact the office promptly for the current notice and board-review schedule.