How are the structure and functioning of state legislatures similar to the united states congress?

State legislatures used to be set up exactly like congress. Each county got more representatives for more population and an even number of representatives in the senate. The states were sovereign so they formed the United States. However, the state formed the counties, the counties did not form the state. Therefore, the state legislature has a certain number of senators and representatives based on population whereas the United States has 2 senators and different number of representatives in the House based on the states population