Washington area players are seeded in nearly every division in the 75th annual national men's and women's squash championships that started yesterday at five clubs here. But the locals are conspicuous in their absence from the top two divisions -- the men's 35-and-under grouping and the women's open.

Although squash has taken firm rooting in many metropolitan centers across the country, it is only in the past few years that the sport has gained substantially in popularity in this area. Most of the area's better players are men in their late 40s who switched from tennis to squash while they were in college.

"Squash has just come of age in Washington in the last five years, and this area has not yet produced its own crop of fine young players," said Don Williams, chairman of, and a participant in, the five-day tournament here. "There are finally programs in place for youngsters and women, as well, but they're still in the developmental stages."

More than 400 of the best squash players from British Columbia to Mexico City are competing here. Women played preliminary matches in their three divisions yesterday. Play in the nine men's divisions begins today.

Squash is now played by more than a million people in the United States. Of the approximately 5,000 squash courts in this country, about 50 are in the Washington area.

Even so, the area will be generally well-represented this weekend. Expected to make a good showing are Alexandria's Ed Reines (35-40 division), Washington's Les Nicholson and Steve Rosenblum (40-45), Alexandria's Williams (45-50) and Annandale's James Carrington (55-60).

Mark Alger and Barbara Maltby, 1981 champions in the top men's and women's divisions, will not be defending their titles. Alger's opponent in last year's final in the men's 35-and-under division, Jay Gillespie of Toronto, is favored to win that class. He will be challenged by John Nimick, the 1981 collegiate champion.

In women's play, No. 2-ranked Alicia McConnell of the University of Pennsylvania will compete with Philadelphia's Gail Ramsey, ranked third in the nation, for the open title.

The matches will be played at the Capitol Hill Squash Club, Washington Squash Racquets Club, University Club of Washington, National Capital YMCA and the Pentagon athletic center.