Where are most oil rigs located?

In the United States, the oil rigs that operate offshore are typically too far away to see. There are many work over or drilling rigs in the Texas, Oklahoma and California but they may only be active in one place for a short time.

I have flown over the Gulf Coast, and seen from the air what appears to be oil rigs, but they may have been producing platforms.

It is far easier to see the pumping units, (pumpjacks) as they are very common in Bakersfield, California.