https://www.schneier.com/blog/archives/2023/01/the-fbi-identified-a-tor-user.html
I bet the NSA tracks all traffic in and out of the US* and can triangulate activity that way. It is also worth noting that if a Tor browser isn't set up right it can still leak a lot of information.
*Possibly a lot of global activity too.
*Possibly a lot of global activity too.
The US has been tracking data on connections going from Denmark the east since 1998.