Rita N. Rivera, an elder of the Tataviam tribe whose ancestors helped build the San Fernando Mission, has died at her Northridge home. She was 86.

Rivera, surrounded by generations of family members, died Sunday of complications of her advanced age.

She often spoke of her heritage, recounting stories of tribal members dating back to the 1850s. She felt so strongly about her heritage that in the late 1960s she helped revive the Fernandeno-Tataviam Tribal Council to represent people with Tataviam roots attempting to get federal recognition.

"She was a tough woman and proud of who she was," said Rudy Ortega Jr., the council's vice chairman. "She was proud when her grandson became a board member. She was thrilled her grandchildren were continuing the tradition."

At the time the Europeans arrived, there were 500 to 1,000 Tataviam in the Santa Clara River Valley in a territory that included such modern-day towns as Piru and Newhall. In an April 22, 1776, diary entry, Spanish explorer Father Francisco Garces wrote upon meeting some Tataviam: "I noticed how mild and approachable the people of this nation are," according to John Johnson, curator of anthropology at the Santa Barbara Museum of Natural History.

Of the various Indian tribes that built the San Fernando Mission, about 30% spoke the Tataviam language, Johnson said.

Rivera was born Rita Newman on March 23, 1915, at her grandmother's house in San Fernando. She remained in her hometown to raise her seven children and five of her 30 grandchildren, often single-handedly due to divorce or a husband's death. She was married four times.

She worked about 50 years as a field laborer, domestic worker and in the cafeterias of Providence Holy Cross Medical Center in Mission Hills, Olive View Medical Center in Sylmar and several San Fernando Valley elementary schools, retiring in 1980. After returning from work, she was known to make a home-cooked meal for her family, even if it meant propping up her tired feet as she crafted homemade tortillas and fried potatoes, her family said.

Rivera is survived by her children, PeeWee Espinoza of Agoura Hills, Raymond Espinoza of North Hills, Darlene Guadiana of Panorama City, Jack Rios of Sylmar, Katherine D. Sarenana of Northridge, Andy Garcia of Sylmar and Richard Gomez of Sylmar; and a sister, Shirley Traba of Sylmar.

A graveside service is planned for 10 a.m. today at San Fernando Mission Cemetery.