Huntsville Unit

Huntsville Unit (HV)
	Location in Texas
Location	815 12th Street; Huntsville, Texas 77342; 30°43′18″N 95°32′48″W / 30.7217°N 95.5466°W;
Status	Operational
Security class	G1–G3, Security Detention, Transient
Capacity	1,705
Opened	1849
Managed by	Texas Department of Criminal Justice
Warden	Kelly Strong
Notable prisoners
	Chad Butler ("Pimp C"), Duane "Dog" Chapman, John Wesley Hardin, Satanta, Doc Middleton Seth Wayne Campbell (first marriage on unit)

Texas State Penitentiary at Huntsville or Huntsville Unit (HV), nicknamed "Walls Unit", is a Texas state prison located in Huntsville, Texas, United States. The approximately 54.36-acre (22.00 ha) facility, near downtown Huntsville, is operated by the Correctional Institutions Division of the Texas Department of Criminal Justice. The facility, the oldest Texas state prison, opened in 1849.

The unit houses the execution chamber of the state of Texas. It is the most active execution chamber in the United States, with 600 (as of May 18, 2026) executions since 1982, when the death penalty was reinstated in Texas.