It varies from state to state.
Federally, DOT requires placarding above 1000 lbs, BUT that weight includes both the contents (in your question, the fuel), AND the container (the fuel tanks).
119 gallons of diesel fuel weighs about 825 lbs, so that sounds reasonable. Diesel is about 12% more dense than gasoline, so under that assumption, you could carry more gasoline than diesel.
BUT, I saw a reference online in California, that limits you to 55 gallons. So, you've got to do your own research, in your own state.