I solved a 30-year old mystery (at least to me) a few days ago! I've been going out to Chiva Falls in Redington Pass ever since I came to Tucson in the early 1980s. Actually, the Chiva Falls trail was the first 4WD trail I ever went on (in my 1977 Jeep CJ5). About a 1/2 mile from Chiva Falls are some old adobe ruins. When I first went there, they were about 4 feet tall, now there isn't much left. The FS designated this is a restoration area about 10 years ago. What I was originally told was that this cabin was part of an old mail route to Tucson. It's a prevalent rumor around Tucson, but I could never verify it. I talked to the FS after they designated it a restoration area and they did not know what it was (maybe I talked with the wrong people).

A few weeks ago I was looking at a 1904 Topo map of the Tucson area and noticed a place called Sheep Camp that appeared to be in the correct area of the adobe ruins. After some calibration of the map, I was able to find the GPS coordinated of Sheep Camp and they matched the location of the ruins! Wow. It wasn't a mail station after all. Here are some current pictures (from this month) and an image of the topo map. I hope to find some of the old pictures I have of the place from the 1980s and post them.
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The crumbling walls of Sheep Camp

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1904 Topo Map

Here's some more information on the trail itself (and another find I made this month there):