Dillon S. Myer, 91, who from 1942 to 1946 was director of the War Relocation Authority, the organization that supervised the wartime movement and relocation of more than 100,000 Japanese Americans from their homes on the west coast, died of cardiac arrest Oct. 21 at the Carriage Hill nursing home in Silver Spring.

A resident of Washington, he had lived in Carriage Hill since March of this year.

The wartime dislocation and internment of Japanese Americans, authorized by Executive Order 9066, is considered one of the darkest pages of this country's history. The order authorized the president to move Americans of Japanese origin, who were considered dangerous to national security, away from their homes near the Pacific coast and into resettlement locations in mountain states and the Midwest.

Mr. Myer was assistant director of the Soil Conservation Service when he was asked to become head of the relocation authority. He recalled those bitter years in a 1972 interview, telling a Post reporter that after becoming head of the authority "it took me about one trip to find out this was something that shouldn't be done. It was a very inhuman thing to do."

He led efforts to do away with the work of the authority and for the return of the Japanese to their homes. In 1946, he received an award from the Japanese American Citizen's League that hailed him as a "champion of human rights and common decency."

In addition to heading the War Relocation Authority, Mr. Myer served in a variety of other posts in government and private industry. After directing the War Relocation Authority, he spent a year as Commissioner of the Federal Public Housing Authority, then was head of the Institute of Inter-American Affairs, an organization providing technical assistance to Latin America, from 1947 to 1950.

For the next three years, he was Commissioner of Indian Affairs. He then left the government and spent five years as executive director of the Group Health Association before retiring in 1958. In later years he was a consultant to the United Nations, taught briefly at the University of Pittsburgh, and chaired a personnel panel for the newly formed Agency for International Development.

Mr. Myer was a native of Hebron, Ohio. He earned a bachelor's degree in agriculture at Ohio State University and a master's degree in education at Columbia University. He worked for agriculture extension organizations in Kentucky, Indiana, and Ohio, before moving here as assistant chief of the Soil Conservation Service in 1935.

Survivors include his wife, Jenness Wirt Myer, who moved to Chevy Chase from Washington last month; three daughters, Mary Jenness Sandmeyer and Elizabeth A. Hall, both of Chevy Chase, and Margaret McFaddin of Rockville, Ind.; two sisters, Mary M. Tobin of Columbus, Ohio, and Alice M. Eikenberry of Cambridge, Ohio, and 11 grandchildren.