ShotHotspot has mapped 15 abandoned places in Weld, Colorado, ranked by how often they're photographed, viewed and voted for. The most popular are Peace Valley School, Old Mill Greeley Armory and Colorado Springs. Some are private property or unsafe, so get permission before you visit.
We don't know whether you're allowed to visit any of these places. Many are private property, closed to the public or unsafe: get permission from the owner or the relevant authority, and take safety precautions.