Several place names mentioned throughout the episodes clearly place the action in post-Civil War Texas, New Mexico, and Arizona.
sˈɛvɹəl plˈeɪs nˈeɪmz mˈɛnʃənd θɹuːˈaʊt ðɪ ˈɛpɪsˌoʊdz klˈɪɹli plˈeɪs ðɪ ˈækʃən ɪn pˈoʊstsˈɪvəl wˈɔːɹ tˈɛksəs, nˈuː mˈɛksɪkˌoʊ, ænd ˌæɹɪzˈoʊnə.