Interstate highways were built as a system of highways with no stops to anywhere in the country. I think in theory they are maintained by the federal governmen

Interstate highways were built as a system of highways with no stops to anywhere in the country. I think in theory they are maintained by the federal government, but in practice, the feds give money to the states because the states each have agencies that deal with roadbuilding contracts etc. I think in contemporary usage, "freeway" and "highway" mostly mean the same thing: no stops.