That’s not true.
Explanation of CBP limitations
Their actions are limited outside of 100 miles from a border (including coastlines), and they also operate with full jurisdiction at 238 different points of entry (such as airports). But they can operate anywhere in the US.
https://www.americanimmigrationcouncil.org/blog/border-patrol-charlotte-atlanta-100-mile-zone/
The 100-mile zone limits Border Patrol’s authority to a certain extent: they cannot board buses or trains outside the zone, nor can they set up fixed vehicle checkpoints. It is, however, within their power to pull a driver over and interrogate them about their immigration status if they have “reasonable suspicion” that they are not a citizen.
Note that the source above is an organization that does advocacy for immigrants’ rights and tries to provide legal counsel to immigrants in detention centers, so any bias they have would be against the CBP.
So they certainly have the authority to operate in Springfield, or anywhere else in the US, at least to some degree.