USS Sam Houston (SSBN-609/SSN-609), an Ethan Allen-class submarine, was the second ship of the United States Navy to be named after Sam Houston (1793–1863), president of the Republic of Texas. Sam Houston was the US Navy's seventh ballistic missile submarine.

The Ethan Allen class of fleet ballistic missile submarine was an evolutionary development from the George Washington class. The Ethan Allen, together with the George Washington, Lafayette, James Madison, and Benjamin Franklin classes comprised the "41 for Freedom" that were the Navy's main contribution to the nuclear deterrent force through the late 1980s.