quality:correction, stylistic:tone
Marriage and children

Twain and Olivia Langdon corresponded throughout 1868. She rejected his first marriage proposal, but Twain continued to court her and managed to overcome her father's initial reluctance. They were married in Elmira, New York in February 1870. She came from a "wealthy but liberal family"; through her, Twain met abolitionists, "socialists, principled atheists and activists for women's rights and social equality ", including Harriet Beecher Stowe, Frederick Douglass, and utopian socialist writer William Dean Howells, who became a long-time friend. The Clemenses lived in Buffalo, New York, from 1869 to 1871. Twain owned a stake in the Buffalo Express newspaper and worked as an editor and writer. While they were living in Buffalo, their son Langdon died of diphtheria in 1872 at the age of 19 months. They had three daughters: Susy (1872–1896), Clara (1874–1962), and Jean (1880–1909). The Clemenses formed a friendship with David Gray, who worked as an editor of the rival Buffalo Courier, and his wife Martha. Twain later wrote that the Grays were " ' all the solace' he and Livy had during their 'sorrowful and pathetic brief sojourn in Buffalo ' ", and that Gray's "delicate gift for poetry" was wasted working for a newspaper.

Starting in 1873, Twain moved his family to Hartford, Connecticut, where he arranged the building of a home next door to Stowe. In the 1870s and 1880s, the family summered at Quarry Farm in Elmira, the home of Olivia's sister, Susan Crane. In 1874, Susan had a study built, an octagonal gazebo, apart from the main house as a surprise to Twain so that he would have a quiet place in which to write and enjoy his cigars.

Twain wrote many of his classic novels during his 17 years in Hartford (1874–1891) and over 20 summers at Quarry Farm. They include The Adventures of Tom Sawyer (1876), The Prince and the Pauper (1881), Life on the Mississippi (1883), Adventures of Huckleberry Finn (1884), and A Connecticut Yankee in King Arthur's Court (1889).

The couple's marriage lasted 34 years until Olivia's death in 1904. All of the Clemens family are buried in Elmira's Woodlawn Cemetery.