This is a list of the National Register of Historic Places listings in Mercer County, Ohio.

This is intended to be a complete list of the properties and districts on the National Register of Historic Places in Mercer County, Ohio, United States. The locations of National Register properties and districts for which the latitude and longitude coordinates are included below, may be seen in an online map.^[1]

There are 30 properties and districts listed on the National Register in the county.

          This National Park Service list is complete through NPS recent listings posted February 16, 2024.^[2]

Current listings

[3]	Name on the Register[4]	Image	Date listed[5]	Location	City or town	Description
1	Cassella Catholic Church and Rectory	More images	July 26, 1979 (#79002822)	State Route 119 in Cassella 40°24′24″N 84°33′03″W / 40.406667°N 84.550833°W / 40.406667; -84.550833 (Cassella Catholic Church and Rectory)	Marion Township
2	Celina Main Street Commercial Historic District	More images	November 30, 1982 (#82001474)	Roughly bounded by Walnut, W. Livingston, Ash, and Warren Sts. 40°32′58″N 84°34′15″W / 40.549444°N 84.570833°W / 40.549444; -84.570833 (Celina Main Street Commercial Historic District)	Celina
3	Chickasaw School and Rectory	More images	July 26, 1979 (#79002848)	Maple St. 40°26′10″N 84°29′35″W / 40.436111°N 84.493056°W / 40.436111; -84.493056 (Chickasaw School and Rectory)	Chickasaw
4	Coldwater Catholic Church Complex		July 26, 1979 (#79002832)	E. Main and 2nd Sts. 40°28′49″N 84°37′42″W / 40.480278°N 84.628333°W / 40.480278; -84.628333 (Coldwater Catholic Church Complex)	Coldwater
5	Fort Recovery Site	More images	November 10, 1970 (#70000509)	State Route 49 40°24′50″N 84°46′51″W / 40.413889°N 84.780833°W / 40.413889; -84.780833 (Fort Recovery Site)	Fort Recovery
6	Matthias Gast House and General Store		December 29, 1978 (#78002139)	State Route 119 in Maria Stein 40°24′28″N 84°28′13″W / 40.407778°N 84.470278°W / 40.407778; -84.470278 (Matthias Gast House and General Store)	Marion Township
7	Sen. Thomas J. Godfrey House		November 26, 1980 (#80003159)	602 W. Market St. 40°32′56″N 84°34′50″W / 40.548889°N 84.580556°W / 40.548889; -84.580556 (Sen. Thomas J. Godfrey House)	Celina
8	Grand Lake St. Marys Lighthouse		June 2, 1982 (#82003614)	Grand Lake St. Marys-Northwood Addition, east of Celina 40°32′36″N 84°28′53″W / 40.543333°N 84.481389°W / 40.543333; -84.481389 (Grand Lake St. Marys Lighthouse)	Jefferson Township
9	Gruenwald Convent		July 26, 1979 (#79002813)	0.5 miles south of Cassella 40°24′01″N 84°33′03″W / 40.400278°N 84.550833°W / 40.400278; -84.550833 (Gruenwald Convent)	Marion Township
10	Immaculate Conception Catholic Church Complex	More images	July 26, 1979 (#79002833)	Anthony and Walnut Sts. 40°33′07″N 84°34′22″W / 40.551944°N 84.572778°W / 40.551944; -84.572778 (Immaculate Conception Catholic Church Complex)	Celina
11	Maria Stein Catholic Church and Rectory	More images	July 26, 1979 (#79002828)	St. John's Rd. and State Route 119 in Maria Stein 40°24′29″N 84°28′22″W / 40.408056°N 84.472778°W / 40.408056; -84.472778 (Maria Stein Catholic Church and Rectory)	Marion Township
12	Maria Stein Convent	More images	May 6, 1976 (#76001490)	St. John's and Rolfes Rd. in Maria Stein 40°24′57″N 84°28′34″W / 40.415833°N 84.476111°W / 40.415833; -84.476111 (Maria Stein Convent)	Marion Township
13	Mendon Town Hall		December 29, 1978 (#78002140)	S. Main St. 40°40′23″N 84°31′07″W / 40.673056°N 84.518611°W / 40.673056; -84.518611 (Mendon Town Hall)	Mendon
14	Morvilius Opera House		February 3, 2022 (#100007396)	101 North Wayne St. 40°24′48″N 84°46′47″W / 40.4132°N 84.7796°W / 40.4132; -84.7796 (Morvilius Opera House)	Fort Recovery
15	Otis Hospital		November 25, 1980 (#80003160)	441 E. Market St. 40°32′58″N 84°33′52″W / 40.549333°N 84.564444°W / 40.549333; -84.564444 (Otis Hospital)	Celina
16	Philothea Catholic Church and Priest House		July 26, 1979 (#79002823)	Philothea Rd. in Philothea, between St. Henry and Coldwater 40°27′03″N 84°39′18″W / 40.450833°N 84.655°W / 40.450833; -84.655 (Philothea Catholic Church and Priest House)	Butler Township
17	Calvin E. Riley House		November 30, 1978 (#78002137)	130 E. Market St. 40°32′55″N 84°34′10″W / 40.548611°N 84.569444°W / 40.548611; -84.569444 (Calvin E. Riley House)	Celina
18	St. Aloysius Catholic Church	More images	July 26, 1979 (#79002824)	U.S. Route 127 and State Route 274, west of Carthagena 40°26′11″N 84°34′12″W / 40.436389°N 84.57°W / 40.436389; -84.57 (St. Aloysius Catholic Church)	Marion Township
19	St. Anthony Catholic Church, Padua	More images	July 26, 1979 (#79002821)	State Route 49 and St. Anthony Rd. in Padua 40°30′32″N 84°47′07″W / 40.508889°N 84.785278°W / 40.508889; -84.785278 (St. Anthony Catholic Church, Padua)	Washington Township
20	St. Bernard Catholic Church and Rectory	More images	July 26, 1979 (#79002842)	Main St. 40°21′08″N 84°38′45″W / 40.352222°N 84.645833°W / 40.352222; -84.645833 (St. Bernard Catholic Church and Rectory)	Burkettsville
21	St. Charles Seminary and Chapel	More images	July 26, 1979 (#79002840)	0.5 miles south of Carthagena, off U.S. Route 127 40°25′57″N 84°33′48″W / 40.4325°N 84.563333°W / 40.4325; -84.563333 (St. Charles Seminary and Chapel)	Marion Township
22	St. Francis Catholic Church and Rectory		July 26, 1979 (#79002837)	Cranberry and Ft. Recovery-Minster Rd. in Cranberry Prairie 40°23′34″N 84°34′55″W / 40.392778°N 84.581944°W / 40.392778; -84.581944 (St. Francis Catholic Church and Rectory)	Granville Township
23	St. Henry Catholic Church	More images	July 26, 1979 (#79002829)	Main St. 40°25′03″N 84°38′15″W / 40.4175°N 84.6375°W / 40.4175; -84.6375 (St. Henry Catholic Church)	St. Henry
24	St. Joseph Catholic Church and Rectory		July 26, 1979 (#79002820)	Sawmill and St. Joe Rds. in St. Joe 40°25′41″N 84°44′19″W / 40.428056°N 84.738611°W / 40.428056; -84.738611 (St. Joseph Catholic Church and Rectory)	Recovery Township
25	St. Paul's Catholic Church and Rectory		July 26, 1979 (#79002827)	Junction of Sharpsburg and Meiring Rds. in Sharpsburg 40°22′02″N 84°42′41″W / 40.367222°N 84.711389°W / 40.367222; -84.711389 (St. Paul's Catholic Church and Rectory)	Gibson Township
26	St. Peter Catholic Church and Rectory		July 26, 1979 (#79002831)	St. Peter and Philothea Rds. in St. Peter 40°27′03″N 84°44′48″W / 40.450833°N 84.746667°W / 40.450833; -84.746667 (St. Peter Catholic Church and Rectory)	Recovery Township
27	St. Rose Catholic Church Complex	More images	July 26, 1979 (#79002838)	Main St. in St. Rose 40°24′26″N 84°30′53″W / 40.407222°N 84.514722°W / 40.407222; -84.514722 (St. Rose Catholic Church Complex)	Marion Township
28	St. Sebastian Catholic Church and Rectory	More images	July 26, 1979 (#79002830)	Sebastian Rd. and State Route 716A in St. Sebastian 40°26′39″N 84°31′00″W / 40.444167°N 84.516667°W / 40.444167; -84.516667 (St. Sebastian Catholic Church and Rectory)	Marion Township
29	St. Wendelin Catholic Church, School, and Rectory	More images	July 26, 1979 (#79002885)	Ft. Recovery-Minster Rd. and Township Line in Wendelin 40°24′00″N 84°41′27″W / 40.4°N 84.690833°W / 40.4; -84.690833 (St. Wendelin Catholic Church, School, and Rectory)	Recovery Township
30	Wallischeck Homestead		November 27, 1978 (#78002138)	North of Fort Recovery 40°26′40″N 84°48′05″W / 40.444444°N 84.801389°W / 40.444444; -84.801389 (Wallischeck Homestead)	Recovery Township