How many elections did Abraham Lincoln lose before becoming president?

Three.

* In 1832, he ran for state legislator and lost.

* In 1854, he was a candidate for U.S. Senator and lost (he threw his support to Free-Soil Democrat Lyman Trumbull, who became a Republican).

* In 1858, he was a candidate for U.S. Senator and lost.

Note: Lincoln was not defeated for re-election as U.S. Representative in 1848; he was not a candidate for re-election. In 1846, Lincoln was elected U.S. Representative from the Illinois 7th Congressional District, in succession to his friend Edward Baker, elected in 1844. In 1843, the Whig Party had nominated John Hardin, but at the same time had endorsed Baker for the 1844 nomination - establishing a single-term rule. This opened the way for Lincoln's election in 1846, but required him to retire in 1848.

Lincoln was also the loser in other political contests, though these are not properly called elections.

* In the 1830s, he was twice nominated for Speaker of the Illinois House of Representatives by the Whig legislators, but as the Whigs were in the minority, was not chosen either time.

* In 1843, he sought the Whig nomination for U.S. Representative, but was passed over at the Sangamon County Whig convention in favor of Edward Baker (who in turn was rejected by the District convention, which chose John Hardin). Note: Illinois was one of 19 states which elected Representatives to the 1843-1844 Congress in early 1843.

* In 1849, after much inducement from his friends, Lincoln allowed his name to be suggested for Commissioner of the General Land Office (a Federal post). He became actively interested when Justin Butterfield of Chicago was put forward, feeling that Butterfield did not deserve the post. However, Secretary of the Interior Thomas Ewing chose Butterfield.

* In 1856, at the Republican convention, Illinois delegates nominated Lincoln for Vice Presidential candidate; Lincoln was not there and did not request this. He received 110 votes out of 567 on an informal ballot, but 253 went to William Dayton of New Jersey. Dayton was chosen with 520 votes on the formal ballot.

Source: Donald, David Herbert (1995) Lincoln