This announcement shared by MPPI, Montessori Public Policy Initiative, explains the Montessori curriculum collaboration for US Montessori schools.  It begins with the Birth to 6 age group.

Please use the link and respond with your input on this endeavor.

https://montessoriadvocacy.org/historic-collaboration-unites-montessori-organizations-to-release-the-us-national-montessori-curriculum/