Prostitution is NOT legal in Las Vegas and police actually do arrest girls on occasion but most of the sex trade goes unpunished because the City is making money off it. By bringing the girls out of the underground the city makes money off the tax that is charged when a person orders an escort and pays with a credit card. Nevada actually has legal prostitution in counties that have less than 400k residents. Clark County (the county where Las Vegas is) has more than 2 million residents. You can drive one hour from Las Vegas and find plenty of legal prostitution.