Bloody Basin agate is named for a remote location in central Arizona, northeast of Phoenix. Whether you choose to enter from I-17 or from Cave Creek, you're looking at 30-35 miles of primitive road through some interesting landscape. There's still speculation about how it got its name. Visit Arizona Agate for more information about the region and a few nice pictures of the material.
There is supposedly an agate mine in the region where this material originates although I've never found it even after several trips to the area. The only geo coordinates to the mine merely drop you at the junction where the I-17 access meets up with the Cave Creek access. Someday I hope to find it, in the meantime I purchased a few pieces from a vendor at the Mesa rock show last January.
I really like working this agate. It's got lots of nice colors and variations, and it takes a great polish.