Norton House (Palm Beach County, Florida)
Norton House Historic District (Cumberland County, Maine)
Norton, Charles H., House (Hartford County, Connecticut)
Norton, William F., House (Franklin County, Maine)
Norton-Burnham House (Jefferson County, New York)
Nortonia Boarding House (Washoe County, Nevada)
Norumbega (Knox County, Maine)
Norumbega Carriage House (Knox County, Maine)
Norway Township Stone House (Fillmore County, Minnesota)
Norwegian Buildings at Heg Park (Racine County, Wisconsin)
Outdoor museum of Norwegian heritage of the area
Norwell Residence (Hamilton County, Ohio)
Norwood (Powhatan County, Virginia)
Norwood (Clarke County, Virginia)
Norwood House (Sussex County, Delaware)
Norwood--Hyatt House (Essex County, Massachusetts)
Notleymere (Madison County, New York)
Noto House (Brazos County, Texas)
Nottoway Plantation House (Iberville Parish, Louisiana)
Noves, Charles W., House (Middlesex County, Massachusetts)
Nowack House (Sheboygan County, Wisconsin)
The first home built in Random Lake.
Nowell-Mayerburg-Oliver House (Johnston County, North Carolina)
Nowlan-Dietrich House (Adams County, Nebraska)
Nowland House (Tioga County, New York)
Nowland, J. Martin, House (Norfolk County, Massachusetts)
Noxontown (New Castle County, Delaware)
Noyes Cottage (Franklin County, New York)
Noyes Mansion (Napa County, California)
Noyes, J.A., House (Middlesex County, Massachusetts)
Noyes, James, House (Essex County, Massachusetts)
Noyes--Parris House (Middlesex County, Massachusetts)
Nuckolls House (Pottawatomie County, Oklahoma)
Nuckolls-Jefferies House (Cherokee County, South Carolina)
Historic home south of Gaffney, SC
Nugent's Crossroad Historic District (Woodford County, Kentucky)
Nuits (Westchester County, New York)
Null House (Baltimore, Maryland)
Numertia Plantation (Orangeburg County, South Carolina)
Nun's Green (Worcester County, Maryland)
Nurre-Royston House (Hamilton County, Ohio)
Nut Grove (Albany County, New York)
Nutting Homestead, The (Oxford County, Maine)
Nutwood (Troup County, Georgia)
Nutwood Place (Champaign County, Ohio)
Nyberg--Swanson House (Broward County, Florida)
Nye House (Dodge County, Nebraska)
Nye, Benjamin, Homestead (Barnstable County, Massachusetts)
Nye, Elnathan, House (Barnstable County, Massachusetts)
O'Bannon Homestead (Cass County, Missouri)
O'Bier House (Webster Parish, Louisiana)
O'Blenis House (Bergen County, New Jersey)
O'Connor House (Pembina County, North Dakota)
O'Dea House (Prince George's County, Maryland)
O'Dell House (Cocke County, Tennessee)
O'Donnell Building (Vanderburgh County, Indiana)
O'Donnell House (Sumter County, South Carolina)
O'Donohue, C. A., House (Suffolk County, New York)
O'Kane--Jacobs House (Franklin County, Arkansas)
O. A. E. Blyberg House (Otter Tail County, Minnesota)
O. Arthur Kirkman House and Outbuildings (Guilford County, North Carolina)
O. B. McFadden House (Lewis County, Washington)
O. B. Sims House (Ellis County, Texas)
O. C. Barber Creamery (Summit County, Ohio)
O. C. Sarles House (Traill County, North Dakota)
O. D. and Ada Dillingham House (Taylor County, Texas)
O. E. Payne House (Lucas County, Iowa)
O. E. Rolvaag House (Rice County, Minnesota)
O. E. Walker House (Mohave County, Arizona)
O. F. and Mary Prigden House (DeWitt County, Texas)
O. F. Short House (Ada County, Idaho)
O. J. Daniels House (Jerome County, Idaho)
O. K. Palmer House (Lewis County, Washington)
O. L. and Josephine Morgan House (Jefferson County, Washington)
O. L. Dunaway House (Faulkner County, Arkansas)
O. L. Price House (Multnomah County, Oregon)
O. P. Wickham House (Pottawattamie County, Iowa)
O. T. Baker House (Lorain County, Ohio)
O. W. Getchell House (Mendocino County, California)
O.B. Grant House (Elk County, Pennsylvania)
O.F. and Lulu E. Fryer House (Jefferson County, Iowa)
O.J. Gendron Ranch (Yakima County, Washington)
O.W. Francis House (Jewell County, Kansas)
Oak Alley Plantation (St. James Parish, Louisiana)
Oak Crest (Isle of Wight County, Virginia)
Oak Dell (Morris County, New Jersey)
Oak Forest (Hanover County, Virginia)
Oak Glen (Newport County, Rhode Island)
Oak Grove (Cumberland County, North Carolina)
Oak Grove (Hampton County, South Carolina)
Oak Grove (Jefferson County, Mississippi)
Oak Grove (Charles County, Maryland)
Oak Grove (Northampton County, Virginia)
Oak Grove (Campbell County, Virginia)
Oak Hill (Fairfax County, Virginia)
Oak Hill (Loudoun County, Virginia)
Oak Hill (Ross County, Ohio)
Oak Hill (Fauquier County, Virginia)
Oak Hill (Marshall County, Kentucky)
Oak Hill (Colonial Heights, Virginia)
Oak Hill (Columbia County, New York)
Oak Hill (Cumberland County, Virginia)
Oak Hill Cottage (Richland County, Ohio)
Oak Hill Estate (Fayette County, Pennsylvania)
Oak Island (Charleston County, South Carolina)
Oak Knoll (Middlesex County, Massachusetts)
Oak Lawn (Amherst County, Virginia)
Oak Lawn (Caroline County, Maryland)
Oak Top (Montgomery County, Tennessee)
Oak Tree Cottage (Calhoun County, Alabama)
Oakcliff (Saratoga County, New York)
Oakdale (Chester County, Pennsylvania)
Oakdale Cotton Mill Village (Guilford County, North Carolina)
Oakdene (Staunton, Virginia)
Oakdene Place (Floyd County, Georgia)
Oakes Estate (Essex County, New Jersey)
Oakes, Edward, House (Middlesex County, Massachusetts)
Oakes, J. J., House (Worcester County, Massachusetts)
Oakes-Wood House (Johnson County, Iowa)
Oakforest (Wake County, North Carolina)
Oakham (Warren County, Tennessee)
Oakhill (Calhoun County, Michigan)
Oakhurst (Sumter County, Alabama)
Oakhurst Links (Greenbrier County, West Virginia)
Oaklana (Bertie County, North Carolina)
Oakland (Halifax County, North Carolina)
Oakland (Hanover County, Virginia)
Oakland (Adams County, Mississippi)
Oakland (Wood County, West Virginia)
Oakland (Meriwether County, Georgia)
Oakland (Weakley County, Tennessee)
Oakland (Charles County, Maryland)
Oakland (Adams County, Mississippi)
Oakland (Sumner County, Tennessee)
Oakland Plantation (Bladen County, North Carolina)
Oakland Plantation (Calhoun County, South Carolina)
Oakland Plantation (Edgecombe County, North Carolina)
Oakland Plantation (Aiken County, South Carolina)
Oakland Plantation House (Charleston County, South Carolina)
Oakland Plantation House (East Feliciana Parish, Louisiana)
Oakland/Henry House (Christian County, Kentucky)
Oaklands (Rutherford County, Tennessee)
Oaklands (Kennebec County, Maine)
Oaklands (Chester County, Pennsylvania)
Oaklands, The (Kalamazoo County, Michigan)
Oaklawn Manor (St. Mary Parish, Louisiana)
Oaklawn Plantation (Natchitoches Parish, Louisiana)
Oakleigh (Mobile County, Alabama)
Oakley (Spotsylvania County, Virginia)
Oakley (Fauquier County, Virginia)
Oakley (Sumner County, Tennessee)
Oakley (Northumberland County, Virginia)
Oakley Hill (Hanover County, Virginia)
Oakley Plantation House (West Feliciana Parish, Louisiana)
Oakley, John, House (Suffolk County, New York)
Oaklyn Plantation (Darlington County, South Carolina)
Oakmont (Pitt County, North Carolina)
Oakmoor (Hopkins County, Kentucky)
Oaks II (Montgomery County, Maryland)
Oaks, The (Hinds County, Mississippi)
Oaks, The (Los Angeles County, California)
Oaks, The (West Feliciana Parish, Louisiana)
Oaks, The (Staunton, Virginia)
Oaks, The (De Soto Parish, Louisiana)
Oakslea Place (Madison County, Tennessee)
Oakview (Marshall County, Mississippi)
Oakwold Plantation House (Avoyelles Parish, Louisiana)
Oakwood (Anne Arundel County, Maryland)
Oakwood (Burlington County, New Jersey)
Oakwood (Salt Lake County, Utah)
Oakwood (Licking County, Ohio)
Oakwood (Howard County, Missouri)
Oakwood (Adams County, Mississippi)
Oakwood (Richland County, South Carolina)
Oakwood (Fauquier County, Virginia)
Oaky Grove (Wake County, North Carolina)
Oaterhoudt Stone House (Ulster County, New York)
Oates House (Henry County, Alabama)
Oatlands (Loudoun County, Virginia)
Obadiah Dingee House (New Castle County, Delaware)
Obediah Barber Homestead (Ware County, Georgia)
Obediah Farrar House (Lee County, North Carolina)
Obediah Shirley House (Anderson County, South Carolina)
Historic home in Honea Path, SC
Obee House (Lake County, Illinois)
Oberg--Metcalf House (Sanpete County, Utah)
Obligation (Anne Arundel County, Maryland)
Ocean County Jail (Ocean County, New Jersey)
Ockers, Jacob, House (Suffolk County, New York)
Octagon Cottage (Barren County, Kentucky)
Octagon House (Muscogee County, Georgia)
Octagon House (Jefferson County, Wisconsin)
Octagon House (Fond du Lac County, Wisconsin)
Octagon House that was once a stop on the Underground Railroad.
Octagon House (Laurens County, South Carolina)
Octagon House (Fairfield County, Connecticut)
Octagon House (Cook County, Illinois)
Octagon House (Fairfield County, Connecticut)
Octagon House (Hampden County, Massachusetts)
Octagon House (Middlesex County, Massachusetts)
Octagon, The (Washington, District of Columbia)
Octagon, The (Seneca County, Ohio)
Odell House (Westchester County, New York)
Odessa Ice Cream Company Building (Lafayette County, Missouri)