Nearctica lists 10 species. ITIS lists over 300.
From yellow to brown or red.
Continent-wide in the US, barely entering Canada. (Most diverse in Africa and Australasia)
Natives are soil-dwelling, introduced species in buildings, one plant-inhabiting.
The species Monomorium pharaonis is introduced, present in the whole world, probably originally from Africa. It is major indoor pest in the US. In colder climates it lives in heated buildings.