You are going to have to narrow it down. Get in there with some spray on cleaner and take it to the spray and wash and get all the junk off it that you can. Then dry it out and get it hot and start looking for the leak. The obvious locations are valve covers, intake manifolds, pan gaskets, front and rear main seals. You can also have leaks at the pressure sensor tap. A faulty postitive crank case ventilator valve will cause pressure build up in the engine and force oil out. So you should check the PVC valve and if not changed recently, you may want to change it.
If you have a main seal leaking that one is an engine pull situation, the others are solveable in the car or with some motor lifting in some cases.
Your exhaust manifold is not leaking oil, but the valve cover gasket above it may be.