Mayor Marion Barry, members of Congress and other dignitaries will be on hand today to salute the city's elderly at the 19th Annual Senior Citizens' Day celebration at the Washington Convention Center.

The program, from 1 to 3 p.m., will include comments from Barry, Del. Walter Fauntroy (D-D.C.) and Rep. Claude Pepper (D-Fla.). Jim Vance, a newscaster for WRC-TV (Channel 4), will be the master of ceremonies.

Public service awards will be presented by Barry to 31 District senior citizens for "meritorious service and dedication to making their communities and the District of Columbia a better place in which to live."

Barry also will give out Golden Age awards to three District residents older than 100 for their "many contributions to the community and untiring dedication in serving others."

Receiving Golden Age awards will be Alice Leftwich, 102; Maude E. Carter, 101; and Rosina Budd Harvey Corruthers Tucker, 101.

As chairman of the sick committee at the Michaux Senior Center, Leftwich coordinates assistance and words of cheer to members of the center who get sick. She also participates in crafts, card games and group discussions.

A native of Rosaryville, Md., Leftwich retired from the General Services Administration in 1947 after 30 years with the federal government. She has 6 children, 15 grandchildren, 52 great-grandchildren and 8 great-great-grandchildren.

Carter, a native of Mount Crawford, Va., moved to the District four years ago to live with her 73-year-old son, Joseph. At the Phillip T. Johnson Senior Center, Carter listens to music and talks with other members of the center.

A Redskins fan, she also follows boxing and basketball, reads the paper each day and enjoys going for rides with her son, said her daughter-in-law, Jessie Carter.

Tucker, born and raised in the District, has been a political activist during much of her life. She helped the late A. Philip Randolph organize the International Brotherhood of Sleeping Car Porters.

She has received numerous awards, including a silver cup for public service from the NAACP. She was selected by the Department of Labor as the representative of labor on their mural commemorating "75 years of progress of American Black Women" at an exposition in Chicago in 1940.

Tucker is the narrator of a documentary produced by the Columbia Historical Society and the Smithsonian Institution titled "A Servant and a Man--The Story of a Pullman Porter." She also wrote a book titled "My Life As I Have Lived It."

The Senior Citizens' Day celebration is part of the activities connected with Older Americans Month, proclaimed nationally by President Reagan and locally by the City Council and Barry.

Today's celebration, which will include music and poetry, is sponsored by the D.C. Office on Aging and is open to all District residents. Events will take place in Room 31 at the convention center.