Describing the growth of the Hispanic population in America as ''tremendous, '' officials of the Census Bureau report that there were 14.6 million Spanish-origin Americans in 1980, making the United States ''the seventh-largest Hispanic nation of the world.''
The census thus confirms statistically a huge influx of immigrants over the past 10 years, the majority coming from Mexico and much of that illegally over the southern border.
In the first official 1980 census total for Hispanics, population director Bruce Chapman said the group rose from 4.5 percent to 6.4 percent of the total population during the decade. The US black population is 26 million and the rapidly expanding Hispanics comprise the second largest minority group. Comparisons are difficult, however, because 2.7 percent of Hispanics are also black.
The Mexican-origin population, by far the largest Hispanic group, nearly doubled during the 1970s, jumping from 4.5 million to 8.7 million. California led all states with 3.6 million, followed by Texas with 2.8 million. Illinois (with 408,000) displaced Arizona (396,000), which ranked third in 1970. The Hispanic tide is spreading out from the Southwest.
Census officials agree that many Hispanics are in the country illegally, but they don't try to estimate the number in this study. Earlier unofficial estimates cite anywhere from 3.5 million to 12 million. Controller General Elmer B. Staats, in his Dec. 2, 1977, annual report, said that the government ''believes that for each illegal alien caught, at least two others get through; the border is a revolving door.'' He said estimates on illegal aliens in the United States range up to 12 million.
The Select Commission on Immigration and Refugee Policy, under Theodore M. Hesburgh, president of Notre Dame University, said in 1981, ''The total number of illegal residents in the US for some recent year, such as 1978, is almost certainly below 6 million, and may be substantially less, possibly only 3.5 million to 5 million.''
For the first time the census breaks down the Hispanic element into four types of origin: Mexican, Puerto Rican, Cuban, and ''other.''
''The Mexican origin population had the most dramatic increase - 93 percent, '' the study says.
Puerto Ricans increased about 600,000, or 41 percent over 1970. The Puerto Rican population now numbers 2,013,945.
Census figures increase debate over the problem of immigration. Donna Alvarado, staff member of the Senate Judiciary Committee, testified at a Brookings Institution symposium in 1981 that, ''The fact is that we have never enforced our immigration laws. We have had an ambivalent attitude, a half-open door, ever since our restricted immigration law was passed in 1916.'' Washington is now debating whether the immigration door will be left half-open or finally closed.