Northern Virginia Community College, the state's largest community college, this fall has recorded the sharpest enrollment decline since the school was founded 19 years ago.

The college, which has campuses in Alexandria and Fairfax, Loudoun and Prince William counties, said yesterday that the number of full-time students dropped 8 percent from 16,737 to about 15,400 this fall.

The enrollment decline has forced officials to scramble for ways to cut programs by $1.2 million this year to compensate for an anticipated loss in tuition, according to college spokesman James Bradley. In the past the college has been able to avoid some of the cuts forced on other Virginia colleges by pointing out that it is located in one of the state's fastest-growing regions.

College President Richard J. Ernst, reached at a meeting of college presidents in Lynchburg, said a continued decrease in the number of students could affect the funding the college receives from the state.

Even so, he said, "In a way, this is a blessing." The drop in students will force Northern Virginia to "begin concentrating on the quality of the programs" rather than merely keep up with the school's burgeoning enrollment.

"Our faculty has been stretched to the hilt in running large classes," Ernst said. "So this will give them the reprieve they've been asking for for many years."

The steady growth in the college's student population since 1981 has forced the school to devote much of its budget to new facilities and part-time staff.

A continued decrease in students, however, could prompt the legislature to deny Northern Virginia funds for the planned expansion of two of its five campuses, he said. The college wants to build several classroom, library and laboratory buildings at its Loudoun and Manassas campuses and add a $12.1 million natural sciences building to the Annandale campus.

Ernst said the college received $152,400 last year to design an $8.9 million project on the Woodbridge campus, which would give it more space there. He said he did not expect that this year's enrollment decline would deter the General Assembly from funding the Woodbridge building.

Ernst said the college has no plans to lay off full-time teachers or staff, but will have to consider curtailing its hiring of part-time employes this year. Bradley said other savings will come from cuts in equipment and data processing services.

State Del. Dorothy S. McDiarmid (D-Fairfax), chairman of the House Education Committee, said the drop in enrollment at Northern Virginia is less than at some of the colleges in the southern part of the state. According to figures released by the Virginia Community College System, 19 of Virginia's 23 two-year colleges showed a drop in the number of students this fall.

Statewide the drop in full-time enrollment was 8.4 percent, with Danville Community College showing the largest drop, 17 percent.

McDiarmid attributed the situation to the nation's prosperity, which she said encourages students to take jobs after high school, rather than continue their education. Another reason, she said, is the increase in in-state tuition, which went from $13.75 per academic credit per quarter to $15.25 this fall.