Montgomery County administers the property tax. It can be paid online at www.mctreas.org or www.mcrealestate.org , by mail, in person, or 24 hour night drop at 451 W. Third St, Dayton, Oh 45422. Types of payments include cash, check, money order, or Visa, Mastercard, American Express, and Discover debit/credit cards. The County office is open Monday through Friday 8 a.m. to 4:30 p.m.