Virginia’s September unemployment rate was 4.2 percent, up 1.2 percentage points from the same time a year ago, and the highest jobless rate for the month since 1996. The Virginia Employment Commission says September’s unemployment was down from 4.6 percent in August, as extra business activities associated with the start of a new school year overrode recent negative economic trends. The state’s September unemployment was well below the national rate of 6.0 percent. Among Virginia’s 134 counties and cities, Arlington County had the lowest unemployment rate at 2.7 percent; Martinsville had the highest, at 12.3 percent.