Professional engineers are licensed in each state, and regulations vary some from state to state. Unless you're planning to move very soon, it would make sense to start the licensing in your state of residence.
The licensing rules are usually available online. Do a google search for "professional engineering board michigan" (without the quotes) and it should pull up the site. Also look up the website of NCEES, which handles a lot of the testing requirements.
Licensing requires adequate education, experience, and two tests. You may need to have the engineering degree evaluated (for a fee) to show if it is equivalent to that normally required. Actual engineering experience should count regardless of where it was at, provided the experience itself is adequate. It should show progressive responsibility and training under other qualified engineers. Reference statements from other engineers will be required, see state rules for details. For the tests, you can get sample questions from NCEES and review books elsewhere that will give you an idea of what they are like. You may have to take the two tests several months apart (IE, pass one before you can take the other).
I don't recall the specifics of the tests, but they may require knowledge of customary US units- check in the NCEES information.
An engineer can work in the US without being licensed if they are working under the supervision of another licensed engineer, or if they are working in various exempt industries (see state rules for exemption). So lack of a license doesn't prohibit one from seeking employment. It would be helpful in seeking employment to have a pretty good idea if licensing was feasible or not, though.
