In 1922 Northern Arizona Normal School President Lynn McMullen and a group of student volunteers constructed McMullen Wall. Located north of the Blome Building, this is one of two locations on campus named after the school's fifth president. The principle material used in the wall's construction is Malpais basalt, a black volcanic rock quarried locally. Designating the north boundary of campus, McMullen Wall separated the school and the town.
Only portions of the wall remain today due to the construction of the High Country Conference Center. Posts of McMullen Wall still stand between Morton Hall and the North Union, and at the corner of Dupont Avenue and Knoles Drive. In 2003 the University incorporated stones from the wall in the construction of the Japanese Teahouse and Gardens on south campus.