While the copyright of U.S. federal government documents is governed by Title 17, Section 105, the copyright on state and local government documents is not. As this Harvard Library web site states:
It turns out that figuring out whether state documents are copyrighted
is a tricky question....
Thankfully, the Harvard Library have created this web site to help people identify
the relevant laws in each state. The U.S. map is a clickable infographic, which gives the viewer a quick indication of whether state documents are protected by copyright or in the public domain. You can then click on a state to receive more details.
This State Copyright Resource Center is worth bookmarking, as is the web site Copyright at Harvard Library.