Hadn't planned on going to Mexico, but...
Drove the 70 odd miles from Gila Bend down US-85 to Organ Pipe National Monument, 8 miles from the Mexican Border. Decided to do the 51 mile Puerto Blanco Drive since I'd done the 21 mile Ajo Mountain Drive last year.
Started out slowly and I was thinking Table Top Wilderness was just as good. Then I got to the mountainous part and things perked up. Took about 30 pictures of Saguaro, Organ Pipe, Ocotillo and Cholla cactus with mountains and ranges in the background.
Got halfway through the drive with no problem. The last part of the loop is right along the Mexican border and parallels Mexico's route 2, a few feet on the other side of a fence. A sign said the road to the right was for authorized vehicles only so I turned left at the fence, the only other way I could turn. But that road became impassable in 100 yards or so.
So I gave voice to a choice word or two. Here I was 30 miles out in the desert and the only way I could go was back against a one way road. Plus I couldn't turn around. So I backed up a ways and finally saw a hole in the fence leading to a wash. I walked the wash the short distance to the road which I thought was US-85 and saw I could drive it with no problem.
I drove up on the road and turned left and started driving. I saw several cars go by with Mexican license plates and then a couple of tractor trailers with Spanish logos. Then came several Mexican restaurants and I noticed the signs were in kilometers and Spanish. After 10 miles it started to dawn on me, maybe I wasn't in the U.S. anymore... and sure enough!
I got to the border crossing and explained to U.S. Customs what had happened and their response was...What? They thought it was hilarious but then told me I was extremely lucky the Federales hadn't got me for being in the country illegally.
Back at the visitor center we tried to determine where I went wrong (before crossing into Mexico) but came to no conclusion. So I went off and did the Ajo Mountain Drive again and came back to Table Top Wilderness for my last night in the area.