Allen Blacker, legislator, pioneer, and civic leader, was born to Dennis and Rachel (Hotsenviller) Blacker in Ross County, Ohio, on February 5, 1832. He was educated in public schools at Frankfort, Ohio. He studied law under Allen G. Thurman and later joined the law offices of McClintock and Smith, a prominent commercial law firm. In 1859 he moved to Nebraska City to serve as clerk of the territorial court. Blacker married Martha Porter Robinson on January 24, 1861, and they eventually had five children. He assumed military service during the Civil War with Company D of the First Nebraska Cavalry, where he was promoted to the rank of major. Blacker was also a war correspondent with the New York Herald and served as judge advocate in St. Louis and Fort Leavenworth, Kansas, during a period of martial law.
In 1865 he resigned his commission and in 1869 moved to El Paso, Texas. He sent for his family in 1873. In 1875 he was elected district judge of El Paso. In 1880 he was a representative to the Texas legislature from the Seventy-fifth District. Blacker was a delegate to the Democratic national convention in 1888. He became city attorney of El Paso in 1866 and held that position through the following year. In 1888 he became an alderman, and in 1890 he was a city judge. When faced with failing health, Blacker moved his family to Cloudcroft, New Mexico, in 1900, where he served as justice of the peace, postmaster, and county commissioner. He returned to El Paso in 1904 and was elected city commissioner. Blacker wrote a treatise on military law that was adopted as the authority on the subject by the United States government. He was also a member of the Grand Army of the Republic. He died on December 26, 1905, in El Paso.