South Carolina 
If you're going to do a commercial structure contract that is valued over $5,000 in South Carolina, you must be licensed by the state. However, check with local jurisdictions for occupational licenses and other requirements.

The USC Gamecocks and Clemson Tigers rivalry is so intense throughout the state that you'll oftentimes see licensing and permitting officials with their walls ablaze with team pride. Do not, do not, do not walk into one of these offices sporting the wrong team logo. Our suggestion is to wear a conservative Brooks Brothers suit and cordovan wingtips with a hard hat fashionably tucked under your arm. Then you'll look like every other construction manager in every other construction brochure and web site in this and every other country and every other world.

To find out if a contractor is licensed in South Carolina, go to licenses. 

Out-of-State Corporations
Corporations doing business in South Carolina should register with the South Carolina Secretary of State to do business in the state. For information click on Secretary of State.