To some Washingtonians, Fairfax County is a foreign land. And in some respects, that's not all bad.

The county's business climate is becoming more internationally diverse, and to prove that point it has just distributed its third annual directory of international services to help its growing market of exporting and importing companies and their supporting firms.

An illustration of the growth of international business in the county is the expansion of the directory from 9 pages last year to 19 this year. Since 1970 the number of exporting and importing firms in the county has risen from 2 to 52.

"Most of them have come in the last five years," said G. H. Buchanan, a spokesman for the Fairfax County Economic Development Authority. "The change in the value of the dollar made it more attractive to locate here. And for some foreigners, Washington, D.C., is known."

Most of the foreign-related business is handled through Dulles International Airport, Buchanan said. Many of the firms are small -- "an office of four or five people and a small warehouse," Buchanan said.

But there are also large firms listed such as Burroughs Corp. and Dynalectron Corp.

The directory lists export management companies, international trade consultants, banks, custom house brokers, trade associations, export packing companies, government services firms, foreign freight forwarders and other services located in the county.

Many of the firms are scattered throughout the county although a number of them are concentrated in Herndon and Sterling, which are close to Dulles, Buchanan said. Most of the goods are high-technology items, he added.

For example, Buchanan said, "There's a man out here who builds a very special optical lens for industrial use. He has a factory that looks like an office. You look in the back and there are people wearing white lab coats grinding out lenses."

Many times the firms begin as marketing offices and grow into full-fledged factories, Buchanan added.

The county's international base should continue to grow. In September a groundbreaking is planned for an international industrial park along the Dulles Access Road. The park was planned by Fred Lienard and his Belgium development firm, Gest Invest.

The park will contain 5 million square feet of office space on 140 acres of 8,000 newly available acres of land along the access highway called the Dulles International Corridor. After checking Richmond, New York, Boston and Toronto, Lienard said he chose Fairfax County.

The park is only about 3 1/2 hours from London via the Concorde, Lienard said when the park was first announced last year.

The new international corridor is expected to bring in more than $1 billion in large-scale commercial and industrial development, county officials said.