Following the marriage of her older sister Mary to Harvard Professor Cornelius Conway Felton (later president of Harvard University), she began socializing with a group of intellectuals in Cambridge, Massachusetts.
In 1846, she met scientist Louis Agassiz at a dinner with Mary and her husband.
Though they wanted to marry, he still had a wife and three children (Pauline, Ida and Alexander) in Switzerland.
His wife died in 1848.
In December 1849—when socially acceptable to wed—Lizzie's father gave his blessing.
They married on April 25, 1850 in Boston, Massachusetts at King's Chapel.
Agassiz organized the household and took care of the finances and the children.
She developed strong relationships with her step-children, Alexander, Ida, and Pauline, and her grandchildren.
She had no children of her own.

After her husband's death in 1873, she continued to devote time to her work and family.
She continued to enjoy traveling, and in 1892, Agassiz ventured with family to the Pacific Coast, specifically California, for three months.

She died on June 27, 1907 in Arlington, Massachusetts of a cerebral hemorrhage.
She is buried in Mount Auburn Cemetery with her husband.
The monument is a boulder selected from the moraine of the Aar Glaciers, near where Agassiz once lived.
Following the marriage of her older sister Mary to Harvard Professor Cornelius Conway Felton (later president of Harvard University), she began socializing with a group of intellectuals in Cambridge, Massachusetts. In 1846, she met scientist Louis Agassiz at a dinner with Mary and her husband. Though they wanted to marry, he still had a wife and three children (Pauline, Ida and Alexander) in Switzerland. His wife died in 1848. In December 1849—when socially acceptable to wed—Lizzie's father gave his blessing. They married on April 25, 1850 in Boston, Massachusetts at King's Chapel. Agassiz organized the household and took care of the finances and the children. She developed strong relationships with her step-children, Alexander, Ida, and Pauline, and her grandchildren. She had no children of her own.
After her husband's death in 1873, she continued to devote time to her work and family. She continued to enjoy traveling, and in 1892, Agassiz ventured with family to the Pacific Coast, specifically California, for three months.
She died on June 27, 1907 in Arlington, Massachusetts of a cerebral hemorrhage. She is buried in Mount Auburn Cemetery with her husband. The monument is a boulder selected from the moraine of the Aar Glaciers, near where Agassiz once lived.
Elizabeth Cabot Agassiz