>>1595912EPA hazards (spills, former uses of land, storage containers, etc).
Easements/right-of-ways (pipe lines, utility lines, etc.)
Mineral rights (what company has them and if you can purchase them or not).
Well water quality and water access.
Utility access (power, sewer, water, etc.)
Upwind neighbors (industrial plants within 100 miles.)
Close neighbors (hill automotive junk yards.)
Nearby highways and airports.
Damaging storm frequency and utility outage frequency.
All of that stuff listed above can make life miserable and/or dangerous for you in short or long term. Next you need to consider the needs of what you intend to use the land for. For instance, if you want to pasture animals on fields you will want to look out for and identify plant-based threats. These can be invasive plants or native plants. Buttercup is a terrible threat to pastured animal health and a field covered with it due to over grazing and other poor pasturing practices can ruin you financially and make your livestock very sick. Fields for growing crops shouldn't have species of weeds that are really terrible for the crops you want to grow, like lambs quarter, amaranth species, bind weed, and the like. You may want to sell something you grow or raise, only to find out that the market in the area is overly saturated with that product and you can't make profit.
Read this image.