The cause of the two-time Newbury Medal winner's death April 19 was not reported.
Konigsburg earned a bachelor degree in chemistry, but once her children were born between 1955 and 1959, she began writing and illustrating children's books -- 20 in all.
Her most well-known, "The Mysterious Files of Mrs. Basil E. Frankeweiler," won the Newbury Medal in 1968, the same year her first novel, "Jennifer, Hecate, McBeth, William McKinley, and Me, Elizabeth," was a Newbury runner-up, her obituary in The Florida Times-Union in Jacksonville reported. She was the only children's book author to have both winner and runner-up for the honor in the same year.
In an interview in 1998, Konigsburg said she had a desire "to write something that reflected my own children's growing up," rather than the privileged lives of many characters she had read in other books, Publishers Weekly reported.
Konigsburg was survived by four children, and several grandchildren and great-grandchildren, her obituary said. Her husband, David Konigsburg, died in 2001.