Title II of the No Child Left Behind Act (NCLB) is intended to increase student academic achievement through strategies such as improving teacher quality and increasing the number of "highly qualified teachers" (HQTs) in the classroom. This Federal policy relies on educational research that demonstrates a connection between student achievement and teacher quality. Although NCLB considers each route that teachers may take to meet HQT requirements as equivalent, research demonstrates that some routes may foster higher student achievement than others; those teachers, who met HQT requirements through these routes, are referred to in this study as "research-based HQTs" (RB-HQTs). The quantitative phase of this mixed methodology explores how northern California secondary mathematics teachers in suburban, urban, and rural schools meet "highly qualified teacher" requirements. The subsequent qualitative phase explores the challenges and promising practices in retention and recruitment of RB-HQTs used by those mathematics departments identified as having a "common" or "distinguished" profile of each respective suburban, urban, or rural sub-sample. This study identifies and reports eight strategies used by mathematics departments that have demonstrated success in retention and recruitment of RB-HQTs. The eight identified strategies, when implemented individually or collectively, may increase the proportion of RB-HQTs and improve student academic achievement in each mathematics department across northern California secondary schools, be it suburban, urban, or rural.