Among dozens of factors that influence mathematics teaching in the elementary classroom, textbooks endure as a significant contributor to the conversation. While teachers have many considerations while lesson planning, the textbook often forms an important launch point in determining what to include in lessons and how to do so. It follows that discrepancies between textbooks and research-recommended pathways for learning may lead to concerns or issues with pacing in the classroom. To explore this idea further, this study examined the alignment between three popular Common Core--aligned textbooks series and learning trajectories with respect to the topic of area measurement. Our findings indicated key differences in the ways textbooks presented area lessons and research-recommended ways of learning area topics, including a lack of appropriate area topic coverage in early grades and a mismatch of timing of concepts in later grades. The results indicated that the standards-based textbooks examined may lack attention to important topics in the pacing of area instruction, and suggest the need to inform both preservice and inservice teachers about the gap between textbook lessons and area learning trajectories so that development steps in area learning trajectory can be included in lesson plans.