“The Effectiveness of A proposed Educational Unit in Geography According to Hess Cognitive Rigor Matrix in Developing the Ability of Geographical Practical Thinking and the Cognitive Holding power for the First-year Secondary Students” Abstract: The research aims at developing the skills of Geographical Practical Thinking and improving cognitive holding power for the first year secondary students. To achieve this purpose, An educational unit in geography has been proposed according to the levels of the Hess Cognitive Rigor Matrix, which based on the idea of integration between Bloom's Modified Classification and the Weeb's Classification of Knowledge. The research specifies four skills for geographical practical thinking: (studying life decisions, understanding contemporary geographical phenomena and issues, solving real world problems, and having the ability to develop a strategic action plan). The research adopted Stevenson's definition of the first and Second-Order Cognitive Holding power. Whereas, the First-Order Cognitive Holding Power (FOCHP) includes the lowest cognitive activities, and the Second-Order Cognitive Holding Power (SOCHP) includes the higher cognitive activities. The research tools represented in Geographical Practical Thinking skills test and the Cognitive Holding power measurement for the first year secondary students (Prepared by the researcher) . The sample of the research consisted of 35 female students from the first secondary grade in one of the schools affiliated to the Tenth of Ramadan Educational Administration. The current research based on the experimental design with single experimental group. The results refer to a statistically significant difference at significance level (0.01) between the average scores of the students of experimental group in the pre and post application for both of the Geographical Practical Thinking test and the Cognitive Holding power measurement test in favor of the post application. The results also led to a positive correlation between the Geographical Practical Thinking Skills and the Cognitive Holding power. The research recommends the necessity of developing the content of geography curricula in the different educational stages according to the levels of the Hess matrix for cognitive accuracy, and the necessity of linking this to the levels of evaluation questions to be a reflection of the thinking levels included in the matrix. Keyword: Matrix Cognitive Rigor (MCR), cognitive holding power (CHP), Geographical Practical Thinking