In Texas, a new open carry law allows people with concealed weapon permits to wear a holstered gun in most public places.
"It's going to be a learning process, there's going to be some growing pain here at the beginning. I'm sure there will be some people that are a little startled, possibly by the sight of someone carrying openly," says Sergeant Ryan Bona.
"We'll handle the calls accordingly just like we've always done."
It comes as California tightens its gun laws- banning firearms in or around schools- even for holders of concealed weapons permits.
BB and pellet guns sold in the golden state will have to have a bright colour like pink to make it clear they are not real.
In Hawaii new signs are posted, warning of a new law. The law is raising the legal smoking age from 18 to 21 and it applies to cigarettes and electronic smoking devices.
A second law there bans e-cigarettes in places where smoking is prohibited.
"Our youth survey shows that a four-fold increase happened in public high school students who use e-cigarettes, from 5 percent in 2011 to 22 percent by 2015," says Lola Irvin from the Department of Health.
Tennessee becomes the first state to create an online registry of people convicted of animal cruelty.
State representative Darren Jernigan supported the measure.
"If you're gonna pull a dog behind your truck, if you're gonna burn a cat, then there needs to be some consequences to your actions," State representative Darren Jernigan.
Among the other new laws taking effect across the country - Washington DC is banning styrofoam food containers.
California has banned drivers and bicyclists from wearing ear buds in both ears or resting them on your ears- closing a legal loophole.
And parents in north Carolina can freeze their children's credit reports to prevent identify theft.