Somewhere along the line, someone planted them in your area. At one time, they were planted as ornamentals around homesteads, to control erosion, and as "fencing" around pastures.
I have a neighbor in his 70s who tells me that he remembers his HS vo. ag. class planting the darned things for erosion control. Birds have been effective in spreading the roses hither and yon.
Hey, I'm one of those 80 year old gizzers.
We live on a gravel road, didn't have much money, so I bought 200 MultiFlora Rose bushes from Henry Field Co. and lined the road. They grew beautifully, about 12 feet high and 12 feet wide. Their white rose flower filled the air in the spring. The Brown Thrush, Mocking bird and others loved it. The road dust kinda rolled up and stayed out. Heck, I did know it was considered a "Noxious Weed".
Well, ultimately they got some kinda disease and died off. Chain sawed them down. That was a huge pile of brush to burn and a lot of roots to grub out. Today they are still present in random parts due to the rose hips spread by the birds, just like cedar, mulberry and many other plants.
The State Extension Service later recommended Pine and Russian Olives as wind breaks etc. Now look at what is happening to my pine and olive trees. They too, are diseased causing me a part time job of cutting 40 year old pines, burning and laboring to get rid of them. But "Hey", I like working outside.....keeps me fit and onery.