The president when Texas was formally annexed as a state (December 29, 1845) was James K. Polk.

However, the annexation process spanned two presidencies:

  • John Tyler
    • Pushed hard for Texas annexation near the end of his term.
* Signed the joint resolution of Congress offering annexation to Texas on **March 1, 1845**.
  • James K. Polk
    • Took office on March 4, 1845.
* Supported Tyler’s annexation plan and, as president, oversaw the final steps.
* Signed the act on **December 29, 1845** , by which the U.S. formally accepted Texas as the **28th state**.

So if you’re answering in one line for “president when Texas was annexed,” the historically standard answer is: James K. Polk was president when Texas was annexed to the United States.

Quick Scoop: Why This Sometimes Confuses People

Many discussions and forum posts point out that Tyler started it, Polk finished it.

  • Texas agreed to annexation terms after the U.S. Congress passed the joint resolution under Tyler.
  • The legal act of statehood — Texas entering the Union on December 29, 1845 — happened under Polk, which is why he gets named in most textbooks.

You can think of it like this: Tyler mailed the invitation, but Polk hosted the actual “welcome to the Union” ceremony.

TL;DR:

  • Resolution offering annexation signed: President John Tyler , March 1, 1845.
  • Texas officially admitted as a state: President James K. Polk , December 29, 1845.

Information gathered from public forums or data available on the internet and portrayed here.