Ohio Revised Code Title XXIII. Courts Common Pleas § 2335.06

(1) Twelve dollars for each full day's attendance and six dollars for each half day's attendance at a court of record, mayor's court, or before a person authorized to take depositions, to be taxed in the bill of costs. Each witness shall also receive reimbursement for each mile necessarily traveled to and from the witness's place of residence to the place of giving testimony, to be taxed in the bill of costs. The board of county commissioners of each county shall set the reimbursement rate for each mile necessarily traveled by a witness in a civil case in the common pleas court, any division of the common pleas court, a county court, or a county-operated municipal court. The rate shall not exceed fifty and one-half cents for each mile.

(2) For attending a coroner's inquest, the same fees and mileage provided by division (A)(1) of this section, payable from the county treasury on the certificate of the coroner.