Washington had reportedly been inspired by her experiences during the American Civil War to found an organization for preserving the shared heritage of women from the North and South of the United States.

Washington was interred beside her mother at the Moncure family burial ground of her sister's estate, "Glencairne", in Falmouth, Virginia.

[1][5][11] Flechir's grandson and Washington's grandfather, Thomas Fletcher, served on the staff of General William Henry Harrison in the War of 1812.

[1] Around 1859, William Washington relocated his family to a plantation at Falmouth in Stafford County, Virginia, located on the north side of the Rappahannock River across from Fredericksburg.

[12][13][14] Following her family's relocation to Falmouth, Washington continued to live a "tranquil life" caring for her father until the American Civil War.

[3] As the battle drew even nearer, Washington "sheltered her father's body with her own" in a trench created by a cannon, and they remained in that position for an entire day.

[1][5][11] During her tenure with the Post Office, Washington was known as "Miss Eugie" and "considered quite attractive and always received a great deal of attention wherever she went".

[16][17][18] The organization's founders emulated the Sons of the American Revolution, founded in New York City on April 30, 1889, which excluded women.

[3][17] According to society tradition, Washington's experiences during the American Civil War "inspired in her a will to assist women from both the North and the South in the worthy cause of preserving their shared heritage".

[19] On October 11, 1890, at 2 pm, the 18 founding members and these four men met at the Stratford Arms in Washington, DC, thus forming the Daughters of the American Revolution.

[16][22] Washington ardently carried out the duties of her offices at DAR, despite suffering with a serious eye condition that made it difficult for her to write.

[13] While visiting a family member in Louisiana around 1870, Washington attended a Catholic mission organized by the Paulists at a neighboring parish.

[25][26][27] Prior to her conversion, Washington consulted with a clergyman at her Episcopal church, and in response to his concern, she replied: "Oh no, I must act up to my convictions and I shall pray hard that you may be given the same grace.

[28] Only "a few acquaintances" among Washington's colleagues and employees in her Post Office bureau knew she was ill, and she worked until a week before her death.

[13][16] In October 1990, the Daughters of the American Revolution held a ceremony at her gravesite to mark the centennial jubilee of the organization's founding.

[37] On October 13, 1999, a year after their own centennial, 21 members of the Daughters of Founders and Patriots of America met at the gravesite to unveil a larger memorial plaque honoring her.