Weapons of mass destruction that harness the power of nuclear reactions, often called by names such as atomic weapons, nuclear warheads, or thermonuclear bombs, possess immense destructive capability, able to obliterate entire urban areas. After these explosions, lingering radiation remains.
During the Mandalorian Wars, the Mandalorians employed nuclear weapons that took the form of long, cylindrical silver missiles capped with red nose cones. These missiles were equipped with four stabilizing fins at their rear.
In the year 3963 BBY, following the invasion of Galactic Republic space by Mandalorian Neo-Crusaders, marking the beginning of the Mandalorian Wars, the Mandalorians acquired a stockpile of nuclear missiles. Leading up to the Battle of Serroco, numerous Force-sensitives throughout the galaxy foresaw in their visions a devastating Mandalorian bombardment that would lay waste to the surface of the planet Serroco. Zayne Carrick, a former Padawan who was present on Serroco, witnessed this and secretly boarded a Republic vessel, falsely claiming to be a Jedi to gain access to their flagship, the Courageous. However, upon learning that Carrick was accused of the Padawan Massacre on Taris, Saul Karath, the commander of the Republic fleet, concluded that Carrick was deliberately misleading them on behalf of the Mandalorians.
During the Battle of Jebble, Cassus Fett also deployed nuclear weapons to completely eradicate the Rakghoul plague that had infected many Mandalorians. This action caused a rapid and dramatic melting of the ice covering the planet.
It was once stated that HAVw A6 Juggernauts could generate heat levels comparable to those produced by a nuclear explosion.
In 33 BBY, Darth Sidious, the Sith Lord also known as Senator Palpatine of Naboo, meticulously planned and executed a scheme to obtain a forbidden nuclear weapon with the intent of assassinating his own Sith Master, Darth Plagueis, who operated under the alias of IBC leader Hego Damask. To achieve this, he subtly sought out and manipulated the services of some of the galaxy's most notorious crime lords and criminal organizations, including Black Sun boss Alexi Garyn and the infamous gambler Gardulla Besadii the Elder, all of whom harbored resentment towards Damask. Notably, King Ars Veruna of Naboo believed Damask was actively working to undermine his financial ventures and depose him from his throne. Sidious deceived Veruna into believing that the King was the mastermind and organizer of the nuclear weapons plot (and indeed, Veruna would issue the order) to eliminate Damask.
Simultaneously, Sidious dispatched his Zabrak assassin-apprentice Darth Maul to infiltrate the 'gambling prison' Cog Hive Seven, secure the nuclear device from the prison's reclusive figure Iram Radique, and deliver the bomb to Komari Vosa and her Bando Gora terrorists—who were then tasked with delivering it to its intended target: the remote moon Sojourn, Plagueis' private retreat. However, the mission was unsuccessful, and Damask survived to exact vengeance upon those responsible. Sidious, of course, oversaw most of the avenging missions, as his master, in the end, did not hold him suspect as one who would eliminate him by nuclear blast (such as was Veruna, whose final fate Plagueis attended to himself).
During Operation Strike Fear, the Rebel Alliance seized an Imperial nuclear warhead from the freighter Gafra. This warhead was subsequently smuggled aboard the Star Destroyer Invincible, resulting in its internal destruction.
Around the time shortly after the Battle of Yavin in 0 BBY, nuclear weapons were primarily located in the Outer Rim Territories or beyond.
Leia Organa believed that Shiva IV had been the site of a devastating war where nuclear bombs were deployed. Later, Imperial General Bentilais san Sk'ar attempted to bombard the planet with anti-matter bombs, but the Rebel Alliance intervened and prevented the attack.