Apart from that, I can't find any mention of '5ND7' in any official database, such as the FAA. However, I did find a document called the 'Bismarck Airport Master Plan Update' on the Bismarck Airport's website. The information is dated; the page where you can find the document says 2019, yet the document itself says it was revised in 2016. The document refers to Kinnischtzke Airfield as a privately owned airport. The GNIS says it was created in 1986, and if we assume that information is correct, at one point this may have been a private airfield, but it is no longer in operation. It should also be noted that I can't find satellite imagery from 1962-1995 which shows me some resemblance of a runway. In the satellite imagery from 1995-1998, we can already see the treerow in place where the runway may have been according to airportnavfinder. But again its a private airfield, so only the property owner or previous property owner will know for sure.