"I don't believe this community's been recognized here," said Abelardo Lopez Valdez, the U.S. State Department's assistant administrator for Latin America and the Caribbean. "It's been kind of underground."

Valdez made the remark as he was about to begin yesterday's "town hall meeting" with about 50 of Washington's most prominent Hispano-Americans at All Souls Unitarian Church at 16th and Harvard streets nw. It was the last of 13 such gatherings attended by the Carter administration's top Hispanic appointees across the country during Hispanic Heritage Week.

Valdez would discover that most of Washington's Latinos would agree with him on at least one point: Washington's Hispanics, indeed, do not feel that they have been recognized.

"We call it the forgotten Latino community," said Sonia Gutierrez, president of Washington's Council of Hispanic Agencies, as she introduced the panel.". . . Even though we are in your own back yard, federal agencies have always succeeded in ignoring us completely."

The purpose of National Hispanic Heritage Week has been acknowledge that Hispanics will soon be the largest minority group in the nation. A minority that already has made the United States the fourth largest Spanish-speaking country in the Western Hemisphere.

As Valdez, Community Services Administration director Graciela Olivarez and other representatives of the departments of Health, Education and Welfare the Housing and Urban Department listened through the course of the long program, it became apparent that Washington's Hispanics not only shared the same problems as others across the country, but have many difficulties that are unique to this area.

They, too, suffer from the high unemployment, language barriers, immigration complications and inadequate housing and education. Like Hispanics everywhere in the United States, they believe they have been undercounted by the census takers, and as such have not received their proper share of government services and programs.

Aida Berio, head of Washington's volunteer Latino Commission, which reports to the mayor's office, told the White House panel yesterday that a poll taken last year indicated that as many as 45 percent of the city's Hispanics were unemployed, only 36 percent of those who were employed receive the minimum wage, and 40 percent had language problems. And while the 1970 census counted 15,671 Hispanics in the District of Columbia in 1970, Berio said she believed a more accurate figure now would be close to 75,000.

Hispanic communities in the United States consist mostly of Cubans in Florida, Mexican-Americans in the Southwest and Puerto Ricans in New York. But in Washington the population is a mixture of people from all over Central and South America. As a result, Latinos here until recently have found it difficult to speak with a unified voice.