A
- Abbot, Maine – John Abbot (treasurer of Bowdoin College)
- Abbott, Texas – Joseph Abbott (Texas politician)
- Abernathy, Texas – Monroe Abernathy (one of the developers of the town)
- Abington, Massachusetts – Anne Venables Bertie, Countess of Abington, Cambridgeshire
- Ackerman, California – John Q. Ackerman (first postmaster)
- Acorn, Humboldt County, California – Alonzo and Elizabeth Acorn
- Adams, California – Charles Adams (landowner)
- Adams, Massachusetts – Samuel Adams
- Adams, New York – John Adams
- Adams, Oregon – John F. Adams (homesteader)
- Adams Station, California – Mary Adams Peacock (tavern owner)
- Adamstown, California – George Adams (founder)
- Addington, California – Joseph and Jess Addington (local farmers)
- Addison, Maine and Addison, Vermont – Joseph Addison (English essayist, poet, playwright and politician)
- Adin, California – Adin McDowell (founder)
- Adrian, Michigan – Roman Emperor Hadrian
- Adrian, Minnesota – Mrs. Adrian Iselin (mother of Adrian C. Iselin, a director of the Sioux City and St. Paul Railroad Company)
- Aguilar, Colorado – José Ramón Aguilar (cattleman and pioneer)
- Albany, New Hampshire – James of York and Albany (indirectly, via Albany, New York)
- Albany, New York – James of York and Albany
- Alberhill, California – C.H. Albers, James and George Hill (landowners).
- Albert Lea, Minnesota – Albert Miller Lea (engineer, soldier, and topographer with the United States Dragoons)
- Alberton, Montana – Albert J. Earling (president of the Chicago, Milwaukee, St. Paul and Pacific Railroad)
- Albuquerque, New Mexico – Francisco Fernández de la Cueva, 8th Duke of Alburquerque
- Alcester, South Dakota – Colonel Alcester of the British army
- Alden, California – S.E. Alden (farmer and landowner)
- Alexander, Maine – Alexander Baring, 1st Baron Ashburton
- Alexandria, California – Alexander C. McSwain (first postmaster)
- Alexandria, New Hampshire – John Alexander (indirectly, via Alexandria, Virginia)
- Alexandria, South Dakota – Alexander Mitchell (railroad president)
- Alexandria, Virginia – John Alexander (settler)
- Alford, Massachusetts – Colonel John Alford
- Alfred, Maine – King Alfred the Great
- Alice, Texas – Alice Gertrudis King Kleberg (daughter of Richard King, who established the King Ranch)
- Allendale, Oakland, California – Charles E. Allen (real estate broker)
- Allentown, Georgia – J.W. Allen (postmaster)
- Allentown, Pennsylvania – William Allen
- Alstead, New Hampshire – Johann Heinrich Alsted (compiled an early encyclopedia that was popular at Harvard College) (note spelling)
- Alton, Illinois – Alton Easton (son of founder Rufus Easton)
- Alvarado, California – Juan Alvarado (Mexican governor of California)
- Alvin, Texas – Alvin Morgan (settler)
- Amador City, California – Jose Maria Amador (early gold prospector)
- Anaheim, California – Saint Anne (indirectly, via the Santa Ana River)
- Anderson, Mendocino County, California – Walter Anderson (founder)
- Anderson, Indiana – Chief William Anderson
- Anderson, South Carolina – Gen. Robert Anderson
- Andersonia, California – Jeff Anderson (sawmill owner)
- Andrade, California – Mexican General Guillermo Andrade
- Angelica, New York – Angelica Schuyler Church
- Angels Camp, California – Henry P. Angel (early settler and merchant)
- Ankeny, Iowa – John Fletcher Ankeny
- Annapolis, Maryland – Anne of Great Britain
- Annette, California – Annette L. Jenness (first postmaster)
- Anson, Maine – George Anson, 1st Baron Anson
- Ansonia, Connecticut – Anson Greene Phelps
- Antis Township, Pennsylvania – Frederick Antes (colonel who fought during the Revolutionary War) (note spelling)
- Applegate, California – Lisbon Applegate (early settler)
- Appleton, Maine and Appleton, Wisconsin – Samuel Appleton (father-in-law of Amos Lawrence, founder of Lawrence University)
- Arbuckle, California – Tacitus R. Arbuckle (early landowner and settler)
- Arco, Idaho – Georg von Arco
- Arlington, Texas – Henry Bennet, 1st Earl of Arlington (indirectly, via Arlington House, The Robert E. Lee Memorial)
- Arnold, California – Bob and Bernice Arnold (early local merchants)
- Arnold Heights, California – General Henry H. Arnold
- Arundel, Maine – Lord Arundel
- Arvada, Colorado – Hiram Arvada Haskin (brother-in-law of settler Mary Wadsworth)
- Arvin, California – Arvin Richardson (pioneer)
- Astor, Florida and Astor Park, Florida – William Backhouse Astor, Sr.
- Astoria, Oregon – John Jacob Astor
- Atkinson, Maine – Judge Atkinson (landholder)
- Atwater, California – Marshall D. Atwater (farmer, landowner)
- Auberry, California – Al Yarborough
- Augusta, Georgia – Princess Augusta of Saxe-Gotha
- Augusta, Maine – Augusta Dearborn (daughter of Henry Dearborn)
- Auld, California – George Auld (first postmaster)
- Ault, Colorado – Alexander Ault (flour mill owner)
- Austin, Minnesota – Austin Nichols (settler)
- Austin, Texas – Stephen F. Austin
- Averill, Vermont – Samuel Averill (landholder)
- Avery, California – George J. Avery (first postmaster)
- Averys Gore, Vermont – Samuel Avery (Westminster deputy sheriff and jailkeeper)
- Ayer, Massachusetts – Dr. James Cook Ayer (patent-medicine manufacturer)
Read more about this topic: List Of American Places Named After People