Pretty much every state has a publicly available vaccine plan that you can read. The variance is pretty big even though it mostly follows the same progression. My stepdad can get the vaccine in phase 1b in his state, but not my mom. The state over from her my mom could get it in phase 1b, but not my stepdad.

My fiancée's parent's can't get it until phase 3 in their state, but they could both get it in phase 1b in my parent's state.