The Sun Belt and the Far West will pick up 11 U.S. House seats at the expense of the Frost Belt as a result of redistricting after the 1980 census, according to studies released yesterday by the Census Bureau.

House seats are reapportioned every 10 years to reflect population shifts revealed in decennial censuses (the overall number of seats remains at 435). In addition, congressional district boundaries are redrawn by the states so that all districts will have about the same population - around 500,000 persons.

The Census Bureau reported that on the basis of population shifts between 1970 and 1978, it appears that California,

The states losing seats: New York, four; Ohio and Illinois, two each, and Pennsylvania, Michigan and South Dakota, one each.

These changes mean that the Sun Belt and the Far West - consisting of the 13 states of the Old South plus California, Oregon, Washington, Arizona, New Mexico, Nevada and Utah - will edge closer to a majority in the House, with 195 seats instead of the present 184.

California, already having the largest delegation, will boost its margin over New York to 45 to 35.

Population shifts within states, mostly from big cities outward, will require extensive redrafting of boundaries within most states, the Census Bureau said.

In Maryland, for example, the total delegation appears to be unchanged at eight members. But while the First Congressional District (Eastern Shore), represented by Robert E. Bauman (R), has gained 18.3 percent in population since 1970, and the Sixth District (Frederick, Howard, Carroll), represented by Beverly Byron (D) has gained 23.3 percent, the city of Baltimore has lost substantial population. The Third District, represented by Barbara Mikulski (D), has lost nearly 12 percent, and the Seventh, represented by Parren J. Mitchell (D), has lost more than 23 percent.

A redrawing of the boundaries of some Maryland districts may be necessary to maintain the principle of one person-one vote mandated by the Supree Court.

Virginia also may require some changes because its Seventh District (represented by Winchester Republican J. Kenneth Robinson) has a population 11 percent higher than the average for the state's 10 districts. But in state's total delegation will probably stay at 10.

The Census Bureau figures show that the vast majority of the fasterest-growing congressional districts are in the South, Far West and Mountain states, while those with the greatest population losses are in the Northeast and Midwest, and usually in cities.

The district with the biggest population gain (64 percent) was California's 43rd, which includes Riverside and Imperial counties. California's 40th district (Orange County and San Diego) had a 60 percent increase in population. The Teas Seventh (part of Houston and surrounding areas) grew 63 percent.

Out of the 30 fastest-growing districts, only three were in Frost Belt areas - Alaska, New York's suburban Suffolk County (Long Island) and Illinois' agricultural 12th District.

The big losers were headed by New York's 21st (the Bronx), with a 39 percent population loss. Michigan's 13th (Detroit) was the second at 29 percent. Of the 30 districts with the biggest losses, 23 were in Frost Belt big cities, six were in older border state cities such as Baltimore, Louisville, Kansas City and St. Louis, and one was in the Old South, Atlanta's Fifth. CAPTION: Map, Winners and Losers in Congressional Reapportionment, The Washington Post