Wikipedia describes a concept called "physiographic provinces". If I understand right, geologists simply created lines on a map, to create clusters of places that are geologically similar.

What I see missing from any articles on physiographic provinces, is what were the characteristics used to define any particular "physiographic province". I am a secondary teacher and need to teach and prepare curriculum about the provinces that my state falls in, so I think if I knew what kinds of characteristics geologists looked at to create each province, I'd know which characteristics to teach the students about.

Is there a list of characteristics that were used to create these groups of provinces?

A comparison with the Rocky Mountains shows the mountains and upland areas are largely supported by granite. The mountains are formed from granite ranges flanked by sedimentary rocks. Rivers are formed in steep, upland glaciated valleys.

At the eastern edge of the Rockies is seen the expansive Great Plains province, a place of completely different typography. The Great Plains province has flat, gentle, rolling typography, with grasslands and broad river valleys.

These are just some examples, without laboring the point. Each province has its own distinctive typography. A good place to look is the Cascade Ranges province. What is the distinctive topographic feature there? (Answer: Typically active volcanoes, such as Lassen Peak in California, or Mount Rainier, Washington, all consequent to the subduction of the Juan de Fuca tectonic plate.)