It's also one of two county seats in Wisconsin that aren't the seats of the county of the same name. The other being Portage.
<Washburn enters the chat>

The FdL rerouting of US 45 I think portends future movement of that route onto I-41 from there to Oshkosh. They probably just did that in town segment for now because it was due for a makeover and WisDOT frequently pays for that when they turn back a state-maintained route. So they took the opportunity to move US 45 off that section.
At some point, I assume they'll get their ducks in a row and move the rest of it and bring 76 down from Oskhosh.
WisDOT is usually kind of dopey with their turnbacks these days; trying to keep them in the same county or whatever. It's silly. They should just go through and trim the fat statewide in one fell swoop of some of these more unnecessary or 'dead end' routes so no one feels like they're losing "their" state highway in favor of a new one somewhere else in the state.