The M L Ranch was established by Henry Clay Lovell and his financial backer Anthony Mason in Wyoming's Big Horn Basin in the late 1870s to the south of the present location.

The second and final location was established farther north as a cattle line camp in 1883 to be closer to markets in Billings, Montana.

The bad winter of 1886–87 killed half the livestock on the ranch, more than 10,000 head., but the M L fared better than most.

In the early 1960s the ranch was purchased by the Bureau of Reclamation as part of the Bighorn Lake reservoir project.

[4][5] The M L Ranch was listed on the National Register of Historic Places on July 15, 1992.