How did Rod find Chris?

In the ending of Get Out, after Rod shows up in a police car to save the day, Chris asks Rod the following:

Rod: I told you not to go in that house.

Chris: I mean... How did you find me?

Rod: I'm TS motherfucking A. We handle shit. That's what we do. Consider this situation ... fucking handled.

It's a hilarious answer which makes for one of the movie's best moments, but it still doesn't answer the question.

How did Rod find Chris at the end of Get Out?

plot-explanation get-out

Best Answer

There are no sourced/concrete answers, so here are some possibilities:

Rod has a friend (friend of a friend) in the FBI or CIA who could track people through the cellphone which Rod used to talk to Chris in previous scenes.
Rod did a simple search based on the name Armitage, which seems to be a popular family, and found the address online. Chris even says:

I'm at the Armitage's house.

When trying to call the police earlier indicating it's a very popular family/house.
Since Rod was taking care of Chris dog, Chris probably left his address in case the dog got sick or something happened with it.