20th Century

10th Street Market (Alameda County, California)
12 Mile road-- Kalamazoo River Bridge (Calhoun County, Michigan)
Concrete arch bridge over Kalamazoo River on 12 Mile Road
12th Avenue South Bridge (King County, Washington)
Steel arch bridge over WA 90 (Dearborn Street) on 12th Avenue S in Seattle
145th Street Subway Station (IRT) (New York County, New York)
14th Avenue South Bridge (King County, Washington)
Lost bascule bridge over Duwamish River on 14th Avenue South in Seattle
1524 Grand Avenue Building (Jackson County, Missouri)
1616 Building (Philadelphia County, Pennsylvania)
1644 Main Street (Richland County, South Carolina)
168th Street Subway Station (IRT) (New York County, New York)
1722-1724 Main Street (Richland County, South Carolina)
181st Street Subway Station (IND) (New York County, New York)
181st Street Subway Station (IRT) (New York County, New York)
1900 Rittenhouse Square Apartments (Philadelphia County, Pennsylvania)
1903 Clinton High School (East Feliciana Parish, Louisiana)
1908 Clovis City Hall and Fire Station (Curry County, New Mexico)
190th Street Subway Station (IND) (New York County, New York)
1911 Kinney County Courthouse (Kinney County, Texas)
1915 Taylor County Courthouse (Taylor County, Texas)
1916 Buffalo High School (Cass County, North Dakota)
1926 Republic National Bank (Dallas County, Texas)
1931 Tempe Bridge (Maricopa County, Arizona)
1938 Clinton High School (East Feliciana Parish, Louisiana)
1938 Lincoln County Courthouse (Lincoln County, Nevada)
20th Century Club (Washoe County, Nevada)
23 Mile Road--Kalamazoo River Bridge (Calhoun County, Michigan)
28th Street Subway Station (IRT) (New York County, New York)
29 Diner (Fairfax, Virginia)
303 Saluda Avenue (Richland County, South Carolina)
310 West Church Street Apartments (Duval County, Florida)
32nd St. and Lancaster Ave. Philadelphia Armory (Philadelphia County, Pennsylvania)
33rd Street Subway Station (IRT) (New York County, New York)
369th Regiment Armory (New York County, New York)
48th Police Precinct Station (Bronx County, New York)
4928 Bryan Street Apartments (Dallas County, Texas)
4K Ranch (Stillwater County, Montana)
4th Avenue Station (IND) (Kings County, New York)
61 16th Street Apartment Building (Fulton County, Georgia)
66 Drive-In (Jasper County, Missouri)
69th Regiment Armory (New York County, New York)
69th Street Transfer Bridge (New York County, New York)
705 Piedmont Avenue Apartments (Fulton County, Georgia)
72nd Street Subway Station (IRT) (New York County, New York)
79th Street Subway Station (IRT) (New York County, New York)
915 E. Pierce Street/Grand Pyramid House (Maricopa County, Arizona)
9th Avenue Station (Dual System BRT) (Kings County, New York)
A & P Food Stores Building (St. Louis, Missouri)
A. A. Hurst House (Jackson County, Iowa)
A. B. Baca House (Socorro County, New Mexico)
A. B. Brewer Building (Stone County, Arkansas)
A. B. C. Dodd House (Floyd County, Iowa)
A. B. Seelye House (Dickinson County, Kansas)
A. C. Foster Building (Denver County, Colorado)
A. C. Freeman House (Charlotte County, Florida)
A. C. Gilruth House (Codington County, South Dakota)
A. C. Steere Elementary School (Caddo Parish, Louisiana)
A. C. Trumbo House (Muskogee County, Oklahoma)
A. D. German Warehouse (Richland County, Wisconsin)
The only Frank Lloyd Wright building in his hometown of Richland Center and a highly endangered landmark.
A. E. C. Cottage No. 23 (Anchorage, Alaska)
A. E. Doyle Cottage (Tillamook County, Oregon)
A. E. Howard House (Yakima County, Washington)
A. E. Larson Building (Yakima County, Washington)
A. E. Taplin Apartment Building (Guilford County, North Carolina)
A. Einar Johnson House (Codington County, South Dakota)
A. Everett Austin House (Hartford County, Connecticut)
A. F. Cappelli Block (Providence County, Rhode Island)
A. F. Dantzler House (Jackson County, Mississippi)
A. F. R. Building (Bannock County, Idaho)
A. G. Becker Property (Lake County, Illinois)
A. G. Long House (Multnomah County, Oregon)
A. G. Newman House (Lincoln County, Idaho)
A. G. Wilson House (Collin County, Texas)
A. H. Brown Public Library (Walworth County, South Dakota)
A. H. Buchan Company Building (Marion County, South Carolina)
A. H. Halff House (Bexar County, Texas)
A. H. Maegly House (Multnomah County, Oregon)
A. H. Stewart House (Canyon County, Idaho)
A. H. Sweet Residence and Adjacent Small House (San Diego County, California)
A. J. Andrus Duplex (Cerro Gordo County, Iowa)
A. J. Hazeltine House (Warren County, Pennsylvania)
A. J. Jackson House (Jones County, Texas)
A. J. Mason Building (Wagoner County, Oklahoma)
A. J. Sherwood House (Coos County, Oregon)
A. J. Stephens House (Lucas County, Iowa)
A. J. Swenson House (Jones County, Texas)
A. J. Williamson House (Hawaii County, Hawaii)
A. K. Steunenberg House (Canyon County, Idaho)
A. L. Kenyon House (Eau Claire County, Wisconsin)
A. M. McNair House (Darlington County, South Carolina)
A. M. Rothschild & Company Store (Cook County, Illinois)
A. M. Scott House (Collin County, Texas)
A. Mendelson and Son Company Building (Albany County, New York)
A. Nanbu Hotel--Holy's Bakery (Hawaii County, Hawaii)
A. O. Huntley Barn (Adams County, Idaho)
A. P. Carter Store (Scott County, Virginia)
A. P. Hill House (Habersham County, Georgia)
A. P. Terry House (Chatham County, North Carolina)
A. R. Carroll Building (Washington County, Arkansas)
A. Robinson Building (Forsyth County, North Carolina)
A. S. Bradford House (Orange County, California)
A. S. Cleveland House (Harris County, Texas)
A. S. Noon Building (Santa Cruz County, Arizona)
A. T. Harris House (Woodford County, Kentucky)
A. T. Jones House (Taylor County, Texas)
A. T. Lewis New Building (Denver County, Colorado)
A. T. Ranch Headquarters (Wheeler County, Nebraska)
A. W. Gridley House (Kane County, Illinois)
Frank Lloyd Wright designed house, now a private residence.
A. W. Hayden House (Bernalillo County, New Mexico)
A. W. Patterson House (Muskogee County, Oklahoma)
A. W. Sillure House (Williamson County, Texas)
A.A. Salazar House (Costilla County, Colorado)
A.B. and Son Hudelson Building (Union County, Oregon)
A.B. Ming House (Yuma County, Arizona)
A.B.C. Storage and Van Company Building (Jackson County, Missouri)
A.E. Moreton Jr. House (Lincoln County, Mississippi)
A.E. Perkins House (Campbell County, Tennessee)
A.G. Gaston Building (Jefferson County, Alabama)
A.G. Pless Jr. House (Galax, Virginia)
A.J. Boss House (Walton County, Georgia)
A.J. Eicholtz House (Brown County, Kansas)
A.L. Cole Memorial Building (Crow Wing County, Minnesota)
A.L. Palmer Building (King County, Washington)
A.L. Wynkoop House (Doniphan County, Kansas)
A.M. Lamb House (Hillsborough County, Florida)
A.P. Dickman House (Hillsborough County, Florida)
A.P. Johnson House (Walworth County, Wisconsin)
A.P. Tureaud Sr., House (Orleans Parish, Louisiana)
A.Z. Palmer House (Navajo County, Arizona)
Aage and Kristine Larsen Homestead (Sheridan County, Montana)
Aaron Barber Memorial Building (Livingston County, New York)
Aaron Copland House (Westchester County, New York)
Aaron Drumright House (Creek County, Oklahoma)
Abandoned Route 66--Cuervo to NM 156 (Guadalupe County, New Mexico)
Abba R. Holman Block (Salt Lake County, Utah)
Abbeville County Courthouse (Abbeville County, South Carolina)
Abbeville Opera House (Abbeville County, South Carolina)
Historic government building & theater in Abbeville, SC
Abbott Graves House (York County, Maine)
Abdou Building (El Paso County, Texas)
Abe Jones House (Oconee County, Georgia)
Abel House (Barton County, Kansas)
Abell house (St. Mary's County, Maryland)
Abercrombie--Cavanaugh House (Angelina County, Texas)
Aberdeen City Hall (Monroe County, Mississippi)
Aberdeen Gardens (Hampton, Virginia)
Abiaca Creek Bridge (Carroll County, Mississippi)
Through truss bridge over Abiaca Creek
Abigail Vare School (Philadelphia County, Pennsylvania)
Abilene Fire Station No. 2 (Taylor County, Texas)
Abner Ellsworth House (Navajo County, Arizona)
Abou Ben Adhem Shrine Mosque (Greene County, Missouri)
Abraham and Carrie Erb House (Yellowstone County, Montana)
Abraham and Phoebe Ball House (Lane County, Oregon)
Abraham Lafkowitz House (Muscogee County, Georgia)
Abraham Lincoln Elementary School (Los Angeles County, California)
Abraham Lincoln High School (Polk County, Iowa)
Abraham Lincoln Memorial Garden (Sangamon County, Illinois)
Abraham Lincoln Statue (Larue County, Kentucky)
Abraham Lincoln Statue and Park (Fayette County, Iowa)
A unique statue of Abraham Lincoln is the centerpiece of a town park
Abraham Lowenstein House (Shelby County, Tennessee)
Abraham Russell Ponder House (Cape Girardeau County, Missouri)
Abraham Tichner House (Multnomah County, Oregon)
Abrams House (Pulaski County, Arkansas)
Abramson House (Monroe County, Arkansas)
Absaroka Mountain Lodge (Park County, Wyoming)
Acacia Lodge (Santa Barbara County, California)
Academia Pomeroy Covered Bridge (Juniata County, Pennsylvania)
Covered bridge over Tuscarora Creek southeast of Academia
Academy of Medicine (Fulton County, Georgia)
Academy of Music (Lynchburg, Virginia)
Academy of Richmond County--1926 Campus (Richmond County, Georgia)
Ace Art Company (Middlesex County, Massachusetts)
Achille Duquesne House (Twin Falls County, Idaho)
Ackerhurst--Eipperhurst Dairy Barn (Douglas County, Nebraska)
Acme Brass and Machine Works Building (Jackson County, Missouri)
Acres, The (Kalamazoo County, Michigan)
Acting Superintendent's Headquarters (Mariposa County, California)