If only someone would make a webpage that lists all of the states' scanner laws and put them in one place.
If only someone would then take that page and put it in the Wiki here so that this question could be answered without asking.
Hmmm...
Per chance a hint to the RR WIKI Scanning Q&A page
Scanning Q&A - The RadioReference Wiki where the info below resides (please note that in the WIKI, there are links following "Read this" or "See this" that didn't copy here):
General Scanning Questions
''Can I bring my scanner on an airplane?''
Read the Scanning on an Airplane and Scanners and Airport Security pages.
''Is scanning legal? How about in my car?''
Read this informative site on scanner laws.
''What is the best scanner for me?''
See the help provided on the scanner decision page.
''What are the codes and signals I hear public safety personnel using on the radio?''
See this article about 10 codes
The RR site already has many answers to these very often answered questions. A simple check of the WIKI and/or a search in the forums would provide a much quicker (and often better) answer than generating a new post.