Basic description (from Cornell Law) of trade secrets
US Code Title 18 Chapter 90 (1996 - 2016)
Uniform Trade Secrets Act (48 states as of Feb. 2017)
Excerpt from a now defunct Trade Secrets Home Page " http://www.execpc.com/~mhallign/42state.html"
Unlike patents, copyrights and trademarks which have been historically protected by national federal legislation, the protection of the intellectual property rights in trade secrets has been protected under state law. However, today, as the result of efforts by the National Conference of Commissioners on Uniform State Laws and the intellectual property bar, 40 states have enacted statutes modeled after the Uniform Trade Secrets Act (UTSA).
Two states (Alabama and Massachusetts) have separate state statutes protecting trade secrets and 8 states (Michigan, Missouri, New Jersey, New York, Pennsylvania, Tennessee, Texas, [Vermont*] and Wyoming) protect trade secrets under the common law.
The following states have Trade Secret statutes that are not modeled after the Uniform Trade Secrets Act:
Alabama 8/12/87 Ala. Code § 8-27-1 et seq.
Massachusetts 1967 Mass. G.L.A. ch. 93 § 42 et seq.
However, The Economic Espionage Act of 1996 (see also http://tradesecretshomepage.com/crime.html) makes a broad range of offenses, involving trade secrets, federal crimes.