The 40 Eridani A Starfleet Construction Yards were 24th century Federation shipyards located in the Vulcan system in the Sol Sector.
The Miranda-class starship USS Brattain was built by Yoyodyne Division at these yards on stardate 22519.5. (TNG: "Night Terrors")
The Nebula-class starship USS Phoenix was built by Yoyodyne Division at these yards on stardate 40250.5. (TNG: "The Wounded")
The Nebula-class starship USS Prometheus was built by Yoyodyne Division at these yards. (DS9: "Second Sight")
It has not been canonically established that 40 Eridani A is located in the Vulcan system until a draft of Geoffrey Mandels Book Star Trek: Star Charts was used in various ENT episodes which shows the location of
"Vulcan (40 Eridani A)".
The existence and location of these shipyards was not known from aired dialogue, but was derived from the text of the starship dedication plaques