CPLR 4511 addresses mandatory judicial notice of such things as the common law, constitutions, and federal and state statutes and codes. It also addresses specified categories of law if a request is properly made; “even in the absence of such request, the court has discretion to take judicial notice on its own motion.” Practice Commentaries, Vincent Alexander, CPLR 4511.

Judicial notice of adjudicative-type facts is a matter of decisional law. The test is whether the fact rests upon knowledge or sources so widely accepted and unimpeachable that it need not be evidentiarily proven, such as calendar dates and geographical locations. Ptasznik v. Schultz, 247 A.D.2d 197 (2d Dept. 1998).