Unemployment in Virginia dipped to 4.6 percent in June, the lowest rate recorded for the month in 14 years, the Virginia Employment Commission said yesterday.

The Lynchburg area registered the highest rate, 5.6 percent, while Northern Virginia had the lowest, 2.5 percent. The number of jobless Virginians actually increased by about 400 in June to 138,900, but a greatly increased labor force caused an unemployment drop from 4.7 percent in May.

The national rate for the month was 6.3 percent.

The June figure, the lowest since the 4.0 percent mark set for the month in 1973, came as the number of people in the labor pool rose over 3 million for the first time ever. The VEC said the increase was due to the number of young people seeking summer jobs, and the seasonal positions they found boosted the number of working Virginians by 47,100 to 2.87 million.

Unemployment usually rises in May and June because of the influx of young job seekers, but the VEC said three factors combined to reverse the trend this year. It said the number of claims remained low in June, the force of young people entering the job market has been decreasing since 1976 because of the reduced birth rate of the early 1970s, and the late closing of many schools because of snow-makeup days meant many younger applicants had not begun their summer vacations when the employment sample was taken in the week of June 7-13.