- Licking
(59 historic properties)
- Logan
(9 historic properties)
- Lorain
(124 historic properties)
- Lucas
(86 historic properties)
- Madison
(11 historic properties)
- Mahoning
(70 historic properties)
- Marion
(14 historic properties)
- Medina
(27 historic properties)
- Meigs
(10 historic properties)
- Mercer
(29 historic properties)
- Miami
(43 historic properties)
- Monroe
(10 historic properties)
- Montgomery
(141 historic properties)
- Morgan
(6 historic properties)
- Morrow
(15 historic properties)
- Muskingum
(80 historic properties)
- Noble
(9 historic properties)
- Ottawa
(29 historic properties)
- Paulding
(4 historic properties)
- Perry
(13 historic properties)
- Pickaway
(28 historic properties)
- Pike
(8 historic properties)
- Portage
(46 historic properties)
- Preble
(18 historic properties)
- Putnam
(10 historic properties)
- Richland
(65 historic properties)
- Ross
(42 historic properties)
- Sandusky
(12 historic properties)
- Scioto
(41 historic properties)
- Seneca
(45 historic properties)
- Shelby
(18 historic properties)
- Stark
(81 historic properties)
- Summit
(159 historic properties)
- Trumbull
(35 historic properties)
- Tuscarawas
(24 historic properties)
- Union
(7 historic properties)
- Van Wert
(6 historic properties)
- Vinton
(10 historic properties)
- Warren
(53 historic properties)
- Washington
(38 historic properties)
- Wayne
(18 historic properties)
- Williams
(7 historic properties)
- Wood
(31 historic properties)
- Wyandot
(10 historic properties)