Nolanville reached its peak as a town between 1890 and 1900 when it went into a holding pattern. A weekly newspaper, the Item, was started by 1896. The first telephone service in Nolanville was started, using barbed wire for lines. There were two lines, a south and a north, with Nolan Creek serving as the dividing line. Nolanville School, one of the larger rural schools in the county in the early twentieth century, had ninety pupils in 1903. The first automobile appeared between 1900 and 1910. It was the automobile that caused Nolanville businesses to decline because it made the trip to Belton or Killeen so much shorter.
In 1921 a new two-story brick school was built, and in 1938 the original part of the present school plant was built. By the mid-1940s the community had 150 to 200 residents, but began to decline after the end of World War II. After dropping to fifty inhabitants in the 1950s, the town began to revive in the 1960s and had 200 residents and six businesses when it incorporated on March 27, 1961. By the late 1960s Nolanville was caught up in the expansion of the Killeen-Fort Hood area, and, as a suburban community, its population shot up to 740 in 1968.
Nolanville Common School District #50 ceased to exist in the spring of 1972. At that time it was annexed to the Killeen Independent School District by the Bell County Board of School Trustees. This action was requested by the Nolanville Board of School Trustees. The Nolanville Common School District was one of only three remaining common school districts in Bell County at that time. It was also uncommon for a school to consolidate because its enrollment and academic needs were greater than its capacity rather than because enrollment had dropped. At one point during the 1970s, because of its reputation as a speed trap, the commanding general of Fort Hood declared Nolanville off-limits to all military personnel. Maps of routes around Nolanville were posted in all company offices.
By 1974, Nolanville's population was 1,050, 1,726 in 1988 and 1,834 in 1990.