First, Las Vegas is not a state but a city within the state of Nevada. According to Wikipedia, common-law marriages can no longer be contracted in Nevada.
Common-law marriage can still be contracted in eleven states (Alabama, Colorado, Iowa, Kansas, Montana, New Hampshire, Oklahoma, Rhode Island, South Carolina, Texas, and Utah) and in the District of...
Only a few states recognize common law marriages: Alabama Colorado Georgia (if created before 1/1/97) Idaho (if created before 1/1/96) Iowa Kansas Montana New Hampshire (for inheritance purposes...
"Currently, only 9 states (Alabama, Colorado, Kansas, Rhode Island, South Carolina, Iowa, Montana, Oklahoma, and Texas) and the District of Columbia recognize common-law marriages contracted within...