Butterfield route ran south of the river from Ozark 1858-1861; 1861 through Reconstruction, mail and coach service in the area was "spotty" at best. By 1871 the Little Rock & Fort Smith Railroad had the main postal route from Memphis to Ozark and was complete to Van Buren / Ft Smith 1872, but stages continued as well where the railroad had no service. Quite possible that it served a Potts or Chidester & Reeside local line pre-war or as part of reconstructed mail service 1866 onward. Also possible that your family's station served communities surrounding Ozark as part of the "Star Route" regional systems post-Civil-War (call it 1871 - 1881 or so.)
Stagecoaches ran local / regional postal routes in parts of the U.S. into the early 20th century. Indians, Civil War, railroads and outlaws didn't make stagecoaches obsolete -- Henry Ford did. FWIW - The last stagecoach route in the U.S. (Tucson - Chandler AZ) shut down toward the end of World War One.
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