My ds in 6th is taking Honors Algebra 1, he took pre-algebra in 5th and is on the same track as Quantum2003 describes with Geometry in 7th and Algebra 2 in 8th. There was one 4th grade boy that skipped up to 5th last year so he is on the same track and 1 year younger. These are all labeled Honors classes and are very rigorous.

This is a middle school 5th through 8th. They have 3 other math classes labeled
Math 1, Math 2, and Foundations of Algebra. Most kids start 5th with Math 2. Everyone in the school is expected to at least pass Honors Algebra 1 by 8th grade.

I am sure there are situations that arise.