How do we know where to look for dinosaur fossils?

The search for dinosaur fossils, as is the search for any kind of fossils, is partly based on knowledge, partly based on good strategy, and partly based on luck. You can't just dig anywhere on the surface of the earth and find them. Basically, dinosaurs lived during the Mesozoic era, and so you have to find rocks that are exposed on the surface of the earth that are of that age, and then you can plan your expedition to go to these localities and look for the particular kinds of dinosaurs that lived during a particular period of time that your studying. Secondly, you have to have rocks of a particular type, when I say particular type, they are usually sedimentary rocks rocks that are deposited by the action of streams or lakes or wind so that they're laid down, and bury these animals. We have found dinosaurs in some very unlikely places, but in general the best dinosaur fossils, and the most abundant fossils, have been found in particular kinds of terrain, mainly deserts. Deserts, that have a lot of cliffs, a lot of hills, a lot of relief, why? Because there's a simple mathematical fact that relates to prospecting. The more surface area you have to look for something, the better your chances are to find a fossil. So walking along a cannon or a cliff face lets you look at more rock per unit area that's why the great, the famous, dinosaur fossil territories are places like the Rocky Mountains and the basins of western North America, the Gobi Desert, and other deserts in central Asia, and South America the deserts in Argentina, especially Patagonia, these are great fossil, dinosaur fossil, hunting territory.