George W. Johnson, dean of the College of Liberal Arts at Temple University, has been named president of Northern Virginia's George Mason University, officials announced yesterday.

The selection of Johnson, who will assume the $42,000 post on July 1, concludes a 10-month nationwide presidential search that started with 283 nominations and applications and narrowed to 14 semifinalists and three finalists.

A university official refused to say if the job had been formally offered to the other two finalists.

George Mason has a 500-acre campus near Fairfax City and 9,200 students enrolled in 40 undergraduate and 17 graduate programs. Founded in 1957 as a two-year extension of the Unversity of Virginia, it became a four-year college in 1966 and gained independent university status in 1972.

It has been without a president since Vergil H. Dykstra resigned last spring.

Louise F. Lowe, executive assistant to the university's board of visitors and staff assistant to the nine-member committee that sought a new president, said George Mason was looking for a person with strong academic credit credentials, administrative skills, experience in dealing with grants, foundations and endowments and "the foresight, courage, energy and strenght to lead a growing university."

Lowe also said the university wanted a person who would help develop endowments and build "community contacts" and "Richmond connections," meaning friends in the state legislature.

She said the applicants included college professors and administrators, lawyers, diplomats and federal government workers.

A native of North Dakota, Johnson received degrees from James College in North Dakota and Columbia University.

He taught at Rutgers University, the University of Misouri and the University of Maryland Overseas before becoming an instructor in English at Temple in 1957.

For the past 10 years, Johnson has served as the dean of the College of Liberal Arts. During that time, the college has expanded to include five major new buildings, a dozen new undergraduate programs and seven new graduate degree programs. It also acquired seven scholarly journals and Phi Beta Kappa chapter.

In announcing the selection of Johnson, John T. hazel Jr., chairman of the George Mason board of visitors, said, "The Board is very much impressed by Dr. Johnson's professional capabilities and by his zest for assuming the leadership on George Mason. He shares the Board's aspirations that this shall become a great modern public university. . ."

Two other Washington area institutions of higher learning - the University of Maryland and Catholic University - are looking for new-presidents.

Maryland offered its presidency last week to John S. Toll. president of the State University of New York at Stony Brook. Toll has said he needs a few weeks to make up his mind.

College presidence have become more difficult to fill as the salaries have become less attrative for the demands and pressures of the jub.

Nationally, the turnover rate for university presidents is 23 percent; an average of 363 presidents of community colleges and four-year institutions change every year.

Lowe, assistant to the committee that picked Johnson for the George Mason presidency, remarked that the search is "a tough job . . . I recently heard that the average tenure (of a university president) is around four to five years."