Traders can be found at the following locations.

Trader	How to unlock
Alexis Combes, Maria Summerset, Horatio, Dr. Penske	Western Commonwealth, Vault 81.
Arturo Rodriguez	Neighborhood; the Fens, Commonwealth Weaponry - Diamond City.
Bean, Crisp, Danny, Reg, Sprocket, Waitron	North Central Commonwealth, Atomics Galleria.
Becky Fallon	Neighborhood; the Fens, Fallon's Basement - Diamond City.
Blake Abernathy and Connie Abernathy	Lexington and Northwest Commonwealth, Abernathy Farm.
Bluejay and Rowdy	Quincy and Southern Commonwealth; Atom Cats Garage.
Deb, Joe Savoldi, Kay, Tony Savoldi	Neighborhood; Charlestown, Bunker Hill.
Deidre	North Central Commonwealth, the Slog.
Doctor Patricia, Deezer, Penny Fitzgerald, Talia McGovern	North Central Commonwealth, Covenant.
Doctor Sun	Neighborhood; the Fens, Doc Crocker's House - Diamond City.
Eleanor	Quincy and Southern Commonwealth, the Trading Post.
Finch	North Central Commonwealth, Finch Farm.
Henry Cooke	Neighborhood; the Fens, Colonial Taphouse - Diamond City.
John	Neighborhood; the Fens, Cathy & John's Super Salon - Diamond City.
June Warwick	Quincy and Southern Commonwealth, Warwick Homestead.
KL-E-0, Daisy, Whitechapel Charlie, Rufus Rubins, Clair Hutchins, Fred Allen	Neighborhood; Financial District, Goodneighbor.
Kawolski	Neighborhood; the Fens, Klean Watur - Sheng Kawolski's House - Diamond City.
Knight-Captain Cade and Proctor Teagan	Coastal Commonwealth, Prydwen.
Leonard Moore	Coastal Commonwealth, Shanty Store.
Moe Cronin	Neighborhood; the Fens, Swatters - Diamond City.
Myrna	Neighborhood; the Fens, Diamond City Surplus - Diamond City.
Polly	Neighborhood; the Fens, Choice Chops - Diamond City.
Random Trader	Lexington and Northwest Commonwealth, Trader's Shack - West of Ranger Cabin.
Robots	Western Commonwealth, Graygarden.
Ronnie Shaw	Neighborhood; South Boston, the Castle.
Scrap Merchant	Ramp overlooking the forest.
Solomon	Neighborhood; the Fens, Chem-I-Care - Diamond City.
Synth Food Vendor and Institute Requisition Vendor	Neighborhood; Cambridge, the Institute.
Takahashi	Neighborhood; the Fens, Power Noodles - Diamond City.
Theodore Collins and Rylee	Coastal Commonwealth, Longneck Lukowski's Cannery.
Tinker Tom and Doctor Carrington	Neighborhood; North End, Old North Church.
Trader	Lexington and Northwest Commonwealth, Small Trading Shack.
Trader	North Central Commonwealth, Rotten Landfill.
Trudy	Lexington and Northwest Commonwealth, Drumlin Diner.
Vadim Bobrov and Yefim Bobrov	Neighborhood; the Fens, Dugout Inn - Diamond City.