Gage Whitney Pace

From West Wing Wiki

The law firm of Gage Whitney Pace is located in midtown Manhattan and is the second-largest law firm in New York. Sam Seaborn worked there before he joined the Bartlet campaign.

Gage Whitney Pace was also mentioned in Aaron Sorkin's Studio 60, Rob Lowe's show Lyon's Den and by character Janis Gold (played by Janeane Garofalo) in 24 and is the "second-largest law firm in D.C."