From the record
“The Cat Creek Oil Field Sign, located about 5 miles (8.0 km) west of the town of Mosby at about mile 150 on Highway 200, in Petroleum County, Montana, was listed on the National Register of Historic Places in 2015.”
Wikipedia article Cat Creek Oil Field Sign, CC BY-SA 4.0.
One of 5 National Register listings published here for Petroleum County · listed in 2015 · category: Object.
Sources: the Wikipedia article · the National Register database, National Park Service