Henkle became a member of the
Maryland House of Delegates in 1863, and served as a member of the State constitutional convention in 1864. He served in the
Maryland State Senate in 1867, 1868, and 1870, and was again a member of the House of Delegates from 1872 to 1875. In 1872, Henkle served as a delegate to the
Democratic National Convention. He was elected as a
Democrat to the Forty-fourth, Forty-fifth, and Forty-sixth Congresses (serving from March 4, 1875 until March 3, 1881). He was an unsuccessful candidate for reelection in 1880 to the Forty-seventh Congress, and moved to
Chicago, Illinois in 1889. == Death ==