Its true location in the was one of the best-kept secrets in the Republic's history.
The lost colony of Sanctuary in the resource-rich Refuge System was discovered in the 1880s PD during the Havenite exploration of a wormhole in the nearby Calvin System. The People's Republic soon started to exploit the system and the planet, creating the Bolthole Complex, a vast shipyard and research facility hidden away from the rest of the Galaxy. (DF)
In the four years following the cessation of hostilities with the Manticoran Alliance, Bolthole's scientists succeeded in developing LAC carriers, modern-standard light attack crafts and pod-laying superdreadnoughts, among other systems.
Despite their best efforts, the intelligence services of the Manticoran Alliance were unable to discover its exact location until the end of the Second Havenite-Manticoran War. It was located in a system on the far side of the Haven Sector with a population of hundreds of millions. (HH11,infodump)
After the total destruction of HMSS Hephaestus, HMSS Vulcan, and HMSS Weyland and the formation of the Grand Alliance, Bolthole became the key R&D facility for the Alliance and its researchers. Admiral Sonja Hemphill and most of the Weyland's surviving researchers departed from Manticore to Bolthole in or around July 1922 PD so that Hemphill and her staff could combine forces with Shannon Foraker to explore further hardware development. The facility would also be the Alliance's primary shipyard. (HH13)
In 1923 PD, Bolthole began an ambitious construction program, building SD(P)s of a common Manticoran-Havenite design. The SD(P)s were built with engines, life support, point defense, counter missile launchers, armor, missile cores and pod rails, broadside weapons, and basic sensors before being transited to the Cassandra Yards in the Sigma Draconis System for installation of Keyhole Two, FTL coms, and current-generations fire control and ECM. The new design was as capable as the Manticoran Invictus class. (HH14)
- David Weber's comment on the origin of Bolthole and the BLS in the Infodump
- Snippet #2 from the Dark Fall novella posted on davidweber.net