The Norwegian (Bokmål) Wikipedia has lists for each county and municipality with all major monuments eligible for the contest. Each list contains the ID number needed when uploading photos for the contest. In addition, the website Kulturminnesøk from the Norwegian Directorate for Cultural Heritage, has all major and minor monuments, including maps for your current location to find what's near. The lists on the Norwegian Bokmål Wikipedia are naturally in Norwegian, but should still be pretty easy to understand no matter what language you speak.
