ATLANTIC CITY, N.J. (AP) — While two-thirds of the country now offers legal sports betting, only six states offer online casino gambling, confounding industry hopes that the rapid growth of sports betting would also bring internet casino wagering along with it.

Speaking Wednesday at the East Coast Gaming Congress in Atlantic City, industry executives and legislators from gambling states offered various explanations for why internet gambling has yet to expand beyond a handful of eastern states.

Internet gambling is legal in New Jersey, Connecticut, Delaware, Michigan, Pennsylvania and West Virg...