Allentown, is a populated place located in Apache County, Arizona, United States. It has an estimated elevation of 6,145 feet above sea level. Allentown got its start c. 1881 when the railroad was extended to that point. The community was named after the railroad construction superintendent Allan Johnson, who in later years returned to the areā¦Allentown, is a populated place located in Apache County, Arizona, United States. It has an estimated elevation of 6,145 feet above sea level. Allentown got its start c. 1881 when the railroad was extended to that point. The community was named after the railroad construction superintendent Allan Johnson, who in later years returned to the area and took to cattle ranching. A post office called Allantown was established in 1924, and remained in operation until 1930.