Fallout 3 locations

General information
Without any of the available add-ons installed, there are 163 marked locations in Fallout 3, provided that the Lawbringer perk and the Contract Killer perk have been selected. Without these, there are 161 as the Regulator HQ and the scrapyard office are not available. The Vault 101 map marker is not counted in the Pip-Boy 3000 "locations discovered" statistic, resulting in a maximum displayed value of 162 discovered locations.

Operation: Anchorage, The Pitt, Broken Steel, Point Lookout, and Mothership Zeta add a total of 10 additional marked locations to the Capital Wasteland map and 52 more on separate world maps, coming to a grand total of 225 marked locations. Of this total, only 221 are counted towards the "locations discovered" statistic in the stats section of the Pip-Boy 3000.

Settlements
Unmarked locations (not marked on the Pip-Boy) are in italic type.

Capital Wasteland
Unmarked locations (not marked on the Pip-Boy) are in italic type.

Washington, D.C.
Unmarked locations (not marked on the Pip-Boy) are in italic type.

Metro
Unmarked locations (not marked on the Pip-Boy) are in italic type.

Broken Steel
Adams Air Force Base can only be accessed if the add-on Broken Steel has been downloaded.

The Pitt
The Pitt can only be accessed if the add-on The Pitt has been downloaded. Unmarked locations (not marked on the Pip-Boy) are in italic type.

Point Lookout
Point Lookout can only be accessed if the add-on Point Lookout has been downloaded. Unmarked locations (not marked on the Pip-Boy) are in italic type.

Mothership Zeta
Mothership Zeta can only be accessed if the add-on Mothership Zeta has been downloaded.