Pierre and Fargo are both cities in the Dakotas: Pierre being the state capital of South Dakota, and Fargo, the most populous city in North Dakota.
Along with Pierre and Fargo, Douglas is also a city in North Dakota.
When Pierre (Tygh Runyan) and Fargo (Neil Grayston) find the "resignation" letter from the files, the old GD logo seen on the letterhead is the one in then-current usage in the pilot, Pilot (2006).