Laws vary from state to state. When you are physically present in a state, even temporarily, you are subject to that state’s laws. You must carry a passport showing that you have leave to enter or remain with you at all times.
The US is an extremely diverse society and attitudes towards LGBT people differ hugely across the country. LGBT travellers may be affected by legislation passed recently in the states of North Carolina and Mississippi. Before travelling please read our general travel advice for the LGBT community. You can find more detail on LGBT issues in the US on the website of the Human Rights Campaign.
Possession or trafficking of a controlled substance in the United States can carry a severe prison sentence and/or fine. Check with each state you are intending to visit to make sure you comply with the personal possession and consumption laws of controlled substances within those states. A list of all types of controlled substances, as listed under the Controlled Substances Act, can be found on the US Department of Justice website.
Details of the assistance offered by the British Embassy and Consulates to British nationals if arrested or detained in the USA is available on GOV.UK.
As we already know, many concerts and events have been cancelled in response to North Carolina's HB2 law such as Bruce Springsteen, Ringo Starr, and Pearl Jam and I just read today that the NBA Commissioner Adam Silver is threatening to move the 2017 All-Star Game from North Carolina if the law doesn't get changed. Many cities across the country are banning non-essential employee travel to the states and unfortunately it is not just North Carolina and Mississippi that are passing these types of "religious liberty" laws. I know first hand being a gay male living in Indiana where Governor Mike Pence passed its version known as Indiana Senate Bill 101, titled the Religious Freedom Restoration Act, although luckily this version was amended to provide LGBT protections only after much public outcry.
I usually try to leave politics out of my posts but I think Ty Cobb from the Human Rights Campaign sums it up best when he states that it is "both frightening and embarrassing that one of our nation's staunchest allies has warned its citizens of the risks" of travelling to the US. "It is now more clear than ever that these terrible measures are not only harming individuals and taking an economic toll on the states, but are also causing serious damage to our nation's reputation, and the perceived safety of LGBT people who travel here."