This article is about the current B973 at Blackburn, Aberdeenshire. For the former B973 in upper Strathdon, see B973 (Strathdon).
The B973 follows the former route of the A96 through the little village of Blackburn to the west of Aberdeen. The number was apparently allocated when the bypass was opened, rather than simply extending the B979 as would have been done elsewhere. This is made even stranger by the fact that the B979 multiplexes with the A96 for some distance to the east before continuing its journey south, so it now also multiplexes, however briefly, with the B973.
Whilst the above route is signed B973 in Blackburn village, is identified as such in Aberdeenshire Council's central highway list, and is marked with that number on OS maps, signage at the road's two junctions with the A96 refers only to the B979.