I'm in the suburbs, for me:

Small = 1 storey

Medium = 2 storeys

Large = 3 storeys, above roofline

Could be perception as it relates to yard size but regions makes a big difference.

North Dakota will not have the towering trees that PNW or the east coast may have.

For me anything over 70' are massive trees. Usually anything more is getting into forest trees, farms steads or champion trees.

The largest sugar maple measured in WI is 99' but others are listed as champion trees in the 60' range. The largest Silver Maple is 96'.

Eastern Cottonwood would likely be the tallest tree here reaching 150' or more. But they don't look at large as say a wide spreading Burr Oak

Actually, Bill's stated sizes match pretty closely (almost dead-on) how arborists classify tree sizing. Except they tend to break it down into only small, medium and large.......no separate classification for 'huge' :-) And tree size is tree size, regardless of location :-)

I should learn the "official" arborist sizes. My neighbor's burr oak and my shingle oak look almost reasonable in my front yard. Until one drops a limb..... Out in the "desirable" neighborhoods they could drop limbs on houses across the street from you.

You know, now that I think about it, I can't remember that burr oak ever dropping a meaningful limb and that thing is 100 foot across. My shingle oak has dropped three notable ones. The wood is a whole other class of hard to cut vs ash I tell ya.

Trees are small here. A big tree is like 60 ft +