President Carter, celebrating the last Christmas of his presidency at home in Plains, Ga., with his family, said yesterday he feels fortunate to have presided over "a nation at peace where brotherly love prevails."

The president and Rosalynn Carter were up before dawn to begin the day's celebrations. The presidential motorcade slipped out of the drive on Woodland Road in Plains and rolled through the fallow peanut fields and pine woods to the Pond House, home of Miss Lillian Carter, the president's mother.

Then, following a long-established family tradition, the Carters went on to the modest bungalow home of Rosalynn Carter's mother, Allie Smith.

"I got a lot of Christmas presents -- shirts, books, tools," the president said.

Rosalynn Carter said her husband had given her a television set "because we don't have one."

In Los Angeles, meanwhile, President-elect Ronald Reagan celebrated Christmas at his Pacific Palisades home with friends and family.

Reagan's four children and his brother attended an afternoon dinner, a family tradition, according to a spokesman for the president-elect. Friends visited later in the afternoon.

A spokesman said Nancy Reagan wanted to keep the family holiday as private as possible by not disclosing information about the family's Christmas Day activities.

Mrs. Reagan declined to reveal the holiday menu, but the president-elect's oldest daughter, Maureen, said turkey and trimmings were the normal fare, with Reagan carving the meat.

There was no word on what the Reagans gave or received as Christmas presents.