I have uploaded the following atlases from Daat Mikra Atlas to help in understanding Zevachim 118b. Please note on the first atlas that Gilgal, Nov, Givon, are in the portion of Binyamin and Jerusalem is on the border.
The second atlas shows the issue with Shilo. While Ephraim does juxtapose Binyamin, Shilo is far north of the Binyamin border and deep into Ephraim territory, as the psukim state that Shilo is north of Beit El. Thus, the only way for Shilo to be in Biyamin is if there was a strip of Binyamin that entered deep into the southern portion of Ephraim.