And to provide some background to what I said earlier about the MwBoS not expanding since the end of Tactics.
At the end of Tactics, no matter which ending is chosen, we see this map of conqered territories
http://hydra-media.cursecdn.com/fallout.gamepedia.com/6/67/FOT_End_D_2.png
Which includes most of the places visited in-game, as well as several places not visited in lower Wisconsin, lower Michigan, and somewhere in central Indiana. This was the MwBoS's territory at the end of 2198.
In 2255 Lyons BoS scourged The Pitt, accidentally leaving Ashur behind, which allowed him to take over. By 2277, Ashur's salver network extended as far as Ronto, which is 317 miles away(by road distance), and included towns like Erie, and D.C. Ashur also compared his city to The Commonwealth, which is 572 miles away.
If we map all of this out we get
https://i.imgur.com/Rs30wyr.png
-The MwBoS and their bunkers/outposts in the Midwest in 2198 are in blue
-The cities Ashur controls/takes slaves from are in black
-Boston, a territory he doesn't take slaves from, but compares his city to, is also marked in blue(because I forgot to change the color)
Now, all the places in grey are all places within the same distance as other cities Ashur takes slaves from. We can see that two of these places, Detroit and Cincinnati are just a stones throw from MWBoS outposts/bases known to exist in 2198.
If the MwBoS had expanded eastward at all in the last 80 years, they would have run into these cities, and become local to Ashur when he set up the Pitt years later. However, Ashur never mentions the MwBoS, or even Chicago, despite them being FAR closer to him then Boston is, indicating that the MwBoS is not likely to have expanded eastwards at all in the 80 years between when we last saw them, and by the time we visit the Pitt in Fallout 3.