Nottawa Stone School (St. Joseph County, Michigan)
Noxen School (Wyoming County, Pennsylvania)
Noyes Hall, State School for the Deaf (Rice County, Minnesota)
Number 18 School in Marshall (Fauquier County, Virginia)
O'Reilly House (St. Johns County, Florida)
Oak Grove Rosenwald School (Sevier County, Arkansas)
Oak Grove School (Forsyth County, North Carolina)
Oak Grove School (Grant County, Arkansas)
Oak Grove School (Hale County, Alabama)
A historic Rosenwald School building in rural Hale County, Alabama.
Oak Grove School, District 20 (Neosho County, Kansas)
Oak Grove Schoolhouse (Hood River County, Oregon)
Oak Hill School (Washington County, Tennessee)
One room schoolhouse in Jonesborough, TN
Oak Lawn School (Cook County, Illinois)
Oak Square School (Suffolk County, Massachusetts)
Oak Street School (Oswego County, New York)
Oak Street School (Androscoggin County, Maine)
Oakdale Public School (Allegheny County, Pennsylvania)
Oakdale School (Jefferson County, Indiana)
Oakland 12 Mile School (Campbell County, Kentucky)
Oakland Park Elementary School (Broward County, Florida)
Oakland Public School (Allegheny County, Pennsylvania)
Oakland School (Marshall County, Oklahoma)
Oates-Reynolds Memorial Building (Dale County, Alabama)
Oats Park Grammar School (Churchill County, Nevada)
Oberlin College (Lorain County, Ohio)
Ocilla Public School (Irwin County, Georgia)
Oconomowoc High School (Waukesha County, Wisconsin)
High School turned Middle School, now serving the community as a 55-unit apartment building
Octagon Stone Schoolhouse (Wayne County, Pennsylvania)
Octagonal Schoolhouse (Kent County, Delaware)
Octagonal Schoolhouse (Essex County, New York)
Ogden High School (Weber County, Utah)
Oglebay Hall (Monongalia County, West Virginia)
Oglesby School (Davidson County, Tennessee)
Ohio Asylum for the Blind (Franklin County, Ohio)
Ohio Stadium (Franklin County, Ohio)
Ohio State Normal College At Kent (Portage County, Ohio)
Ohiowa Public School (Fillmore County, Nebraska)
Oil Springs High School Gymnasium (Johnson County, Kentucky)
Oklahoma City University (Oklahoma County, Oklahoma)
Oklahoma Military Academy Auditorium (Rogers County, Oklahoma)
Oklahoma Military Academy Field House (Rogers County, Oklahoma)
Oklahoma Presbyterian College (Bryan County, Oklahoma)
Okolona College (Chickasaw County, Mississippi)
Oktaha School (Muskogee County, Oklahoma)
Ola School (Gem County, Idaho)
Old Albany Schoolhouse (Nemaha County, Kansas)
Old Arkansas City High School (Cowley County, Kansas)
Old Armijo School (Bernalillo County, New Mexico)
Old Batesburg Grade School (Lexington County, South Carolina)
Old Batesburg-Leesville High School (Lexington County, South Carolina)
Old Biology Hall (Madison County, New York)
Old Bowdoin Center School (Sagadahoc County, Maine)
Old Brown's Mill School (Franklin County, Pennsylvania)
Old Brownson School (Victoria County, Texas)
Old Castle Hall, Baker University (Douglas County, Kansas)
Old Catonsville High School (Baltimore County, Maryland)
Old Center School (Cuyahoga County, Ohio)
Old Central High School (Berkshire County, Massachusetts)
Old Central High School (Kalamazoo County, Michigan)
Old Central University (Madison County, Kentucky)
Old Centre, Centre College (Boyle County, Kentucky)
Old Chappells School (Newberry County, South Carolina)
Former school currently utilized as a community center for the Town of Chappells
Old Christiansburg Industrial Institute (Montgomery County, Virginia)
Old Cokesbury and Masonic Female College and Conference School (Greenwood County, South Carolina)
Historic Female College in Cokesbury, SC
Old College (McMinn County, Tennessee)
Old Cranbury School (Middlesex County, New Jersey)
Old Custom House (York County, Virginia)
Old District 40 School (Osage County, Oklahoma)
Abandoned Stone School
Old District Nine Schoolhouse (Lorain County, Ohio)
Old East, University of North Carolina (Orange County, North Carolina)
Old Eton Elementary School (Murray County, Georgia)
Old Euclid District 4 Schoolhouse (Cuyahoga County, Ohio)
Old Farm Schoolhouse (Hartford County, Connecticut)
Old Fort Pierre School (Stanley County, South Dakota)
Old Frankfort Stone High School (Clinton County, Indiana)
Old Garfield School (Marion County, Oregon)
Old Georgetown High School (Williamson County, Texas)
Old Germantown Academy And Headmasters' Houses (Philadelphia County, Pennsylvania)
Old Goucher College Buildings (Baltimore, Maryland)
Old Greenwood High School (Greenwood County, South Carolina)
Historic school in Greenwood, SC
Old Harvard Yard (Middlesex County, Massachusetts)
Old Hattiesburg High School (Forrest County, Mississippi)
Old Hidalgo School (Hidalgo County, Texas)
Old Hoopes School (Mifflin County, Pennsylvania)
Old Indian Meeting House (Barnstable County, Massachusetts)
Old Jacoby Creek School (Humboldt County, California)
Old Jefferson School (Cape Girardeau County, Missouri)
Old Junction City High School (Geary County, Kansas)
Old Kaw Mission (Morris County, Kansas)
Old La Grange Schoolhouse (Stanislaus County, California)
Old Ladore School (Moffat County, Colorado)
Old Lenox College (Delaware County, Iowa)
Old Library Building (Pima County, Arizona)
Old Louisiana Academy (Ste. Genevieve County, Missouri)
Old LSU Site (Rapides Parish, Louisiana)
Old Lyford High School (Willacy County, Texas)
Old Lynn High School (Essex County, Massachusetts)
Old Main (Henry County, Iowa)
Old Main (Delaware County, Pennsylvania)
Old Main (Clay County, South Dakota)
Old Main (Staunton, Virginia)
Old Main (Coles County, Illinois)
Old Main (Pierce County, Washington)
Old Main (Albany County, Wyoming)
Old Main and Chemistry Building (Delaware County, Pennsylvania)
Old Main and Science Buildings (Iron County, Utah)
Old Main, Almira College (Bond County, Illinois)
Old Main, Augustana Academy (Lincoln County, South Dakota)
Old Main, Augustana College (Rock Island County, Illinois)
A dolomite-clad building in the Renaissance Revival style from the 19th Century
Old Main, Bethany College (Brooke County, West Virginia)
Old Main, California State College (Washington County, Pennsylvania)
Old Main, Dr. Martin Luther College (Brown County, Minnesota)
Old Main, Knox College (Knox County, Illinois)
Old Main, Macalester College (Ramsey County, Minnesota)
Old Main, Mankato State Teachers College (Blue Earth County, Minnesota)
Old Main, Marshall University (Cabell County, West Virginia)
Administration building for Marshall University in Huntington, WV
Old Main, Nebraska Wesleyan University (Lancaster County, Nebraska)
Old Main, Pembroke State University (Robeson County, North Carolina)
Old Main, St. Olaf College (Rice County, Minnesota)
Old Main, Suomi College (Houghton County, Michigan)
Old Main, University of Arizona (Pima County, Arizona)
Old Main, University of Arkansas (Washington County, Arkansas)
Old Main, Utah State University (Cache County, Utah)
Old Main, Western Washington State College (Whatcom County, Washington)
Old Main--Gustavus Adolphus College (Nicollet County, Minnesota)
Old Maxwell Hutterite Colony (Hutchinson County, South Dakota)
Old McKinley High School (Stark County, Ohio)
Old Medford High School (Middlesex County, Massachusetts)
Old Medical College Building (Richmond County, Georgia)
Old Medical College Historical Area (Spalding County, Georgia)
Old Middletown High School (Middlesex County, Connecticut)
Old Mission House (Yukon-Koyukuk Census Area, Alaska)
Old Monroe School House (Sussex County, New Jersey)
Old Morrison, Transylvania College (Fayette County, Kentucky)
Old Nacogdoches University Building (Nacogdoches County, Texas)
Old Nazareth Academy (Victoria County, Texas)
Old New Bloomington School (Marion County, Ohio)
Stone trimmed brick school
Old Newark Comprehensive School (New Castle County, Delaware)
Old Normal School Building (Calloway County, Kentucky)
Old North Tower, Central State College (Oklahoma County, Oklahoma)
Old Ocean Springs High School (Jackson County, Mississippi)
Old Ohio Union (Franklin County, Ohio)
Old Palm Beach Junior College Building (Palm Beach County, Florida)
Old Pathology Building (Marion County, Indiana)
Old Portlock School #5 (Chesapeake, Virginia)
Old Presbyterian Theological Seminary (Jefferson County, Kentucky)
Old Queen's (Middlesex County, New Jersey)
Old Rainey Road Schoolhouse (Anderson County, South Carolina)
Old schoolhouse ruins near Starr, SC
Old Redmond Schoolhouse (King County, Washington)
Old Richmond Schoolhouse and Gymnasium (Forsyth County, North Carolina)
Old Riverside Hutterite Colony (Beadle County, South Dakota)
Old Rock School (Iowa County, Wisconsin)
Old Rock School (Crawford County, Wisconsin)
Old Rockville High School and East School (Tolland County, Connecticut)
Old Russet School (Johnston County, Oklahoma)
Abandoned School Building
Old San Antonio Hospital (San Bernardino County, California)
Old School House (Hillsborough County, Florida)
Old School Privy (Ottawa County, Ohio)
Old Schoolhouse (Burlington County, New Jersey)
Old Schoolhouse (York County, Maine)
Old Seminary Building (Gwinnett County, Georgia)
Old Skedee High School (Pawnee County, Oklahoma)
Single-story red brick school
Old Springdale High School (Washington County, Arkansas)
Old St. Mary's School (Washington County, Ohio)
Old State Capitol (Baldwin County, Georgia)
Old Sutton High School (Braxton County, West Virginia)
Old Troy Hospital (Rensselaer County, New York)
Old Tubac Schoolhouse (Santa Cruz County, Arizona)
Old Union School (Morrow County, Ohio)
Old Union School (Coshocton County, Ohio)
Old Union School (Randolph County, Arkansas)
Old Union School Building (Erie County, Ohio)
Old University Library (Lancaster County, Nebraska)
Old Ursuline Convent (Orleans Parish, Louisiana)
Old Weber School (San Joaquin County, California)
Old Wesson Public School Building (Copiah County, Mississippi)
Old West Haven High School (New Haven County, Connecticut)
Old West, Dickinson College (Cumberland County, Pennsylvania)
Olga School (Lee County, Florida)
Olive Civic Center (Orange County, California)
Olive Township District No. 1 School (Ottawa County, Michigan)
Oliver School (Clark County, Kentucky)
Olmsted Station Powerhouse (Utah County, Utah)
Olney Elementary School (Philadelphia County, Pennsylvania)
Olney High School (Philadelphia County, Pennsylvania)
Olympia School (Martin County, Florida)
Omaha High School (Douglas County, Nebraska)
Omro High School, Annex and Webster Manual Training School (Winnebago County, Wisconsin)
Former school complex repurposed as assisted living for senior citizens
Oneida Stake Academy (Franklin County, Idaho)
Oquirrh School (Salt Lake County, Utah)
Oran District No. 22 Schoolhouse (Onondaga County, New York)
Orange City Colored School (Volusia County, Florida)
Orange High School (Orange County, Virginia)