Rose K. Dawson, 83, who retired in 1969 after 30 years as Republican clerk of the Montgomery County Board of Election Supervisors, died Wednesday at her Rockville home. She had a heart ailment.

A political fixture in Montgomery County for many years, Miss Dawson first began working for the Election Board in 1939. She got the job through her late brother, Walter Dawson, a former state's attorney who then was Republican chairman. Twenty-eight years later, both Democrats and Republicans combined efforts to pass special legislation enabling her to keep her post past the mandatory retirement age of 70.

The legislation, known around the Annapolis State House as "The Rose Dawson Bill," was introduced in the Maryland Senate by then Democratic State Sen. Blair Lee III, who later became the state's governor, and in the House by a Republican delegate from Montgomery County, Daniel J. Cronin.

Two years later, after 34 elections and the addition of 185,000 voters, Miss Dawson retired.

"I'll be 73 in June. Good God, I don't want to go out of here on crutches. I want to get out while I can still hop a little," she told a reporter in a 1969 Washington Post interview.

Miss Dawson was a member of one of Montgomery County's oldest families. But she was born and grew up on the Pine Ridge Indian Reservation in South Dakota. Her father ran a trading store and cattle business in South Dakota until 1911, when he decided to move back to the family home in Montgomery County.

After graduating from the old Rockville High School, Miss Dawson worked for the government and for the County Liquor Control Board. When the Democrats came into power in the late 1930s Miss Dawson lost her job with the liquor board. It was then that her brother arranged for her to join the election board as clerk, until then a part-time position.

Miss Dawson's original family home, "the old Dawson house," became the headquarters for the Montgomery County Historical Society, of which she was a charter member.

Her own house at the time of her death was on family property near "the old Dawson house." she remained active in Republican politics and in behalf of research for cystic fibrosis and mental retardation.

Survivors include a brother, Henry A. (Joe) Dawson, of St. Petersburg, Fla. CAPTION: Picture, ROSE K. DAWSON, 1969 Photo