William Henry Herndon (December 25, 1818 – March 18, 1891) was an American lawyer and politician who was a law partner and biographer of President Abraham Lincoln.

James' father, Revolutionary War veteran Joel Maxcy, arrived in Sangamon County in 1827 with his second wife and died the following month.

The following summer, on July 31, 1861, Herndon married Anna Miles with whom he had three more children: Nina Belle, William and Minnie.

[6] Following this, he returned to Springfield and clerked at the Joshua Speed store, where he often engaged in debates, discussions, and poetry readings with Abraham Lincoln.

Their conversations and readings were sometimes practice sessions before presenting material to the Young Men's Lyceum, where both Herndon and Lincoln were members.

Lincoln also joined the Republican Party, hoping to "fuse" people of disparate political affiliations who wanted to end slavery.

[4][7][8] Herndon loved to learn and developed "one of the best private libraries in Springfield" including works by historians, economists, humanists, free-thinkers and philosophers.

"[13] During political campaigns, Herndon made strong points that tended to alienate members of the Republican Party and swing voters.

However, he executed an important task during that campaign by conducting opposition research in the Illinois State Library to be used against Stephen A. Douglas in the 1860 presidential race.

He also admitted that his frustration with Lincoln's overly permissive parenting of his two younger sons, Willie and Tad, whom he recalled as undisciplined and disruptive brats in the law offices, caused some harsh words during their partnership.

Herndon aspired to write a faithful portrait of his friend and law partner, based on his own observations and on hundreds of letters and interviews he had compiled for the purpose.

He was determined to present Lincoln as a man, rather than a saint, and to reveal things that the prevailing Victorian era conventions said should be left out of the biography of a great national hero.

[23] Herndon's Lincoln: The True Story of a Great Life, the result of their collaborations, appeared in a three-volume edition published by Belford, Clarke & Company in 1889.

[29] Herndon died March 18, 1891,[1] at his farm in Fancy Creek Township, Sangamon County, Illinois north of Springfield.