This study links the concept of Pythagoras to Banten culture. Banten culture has ethnomathematical elements, especially the Pythagorean concept. The concept of Pythagoras in Banten culture includes the construction of buildings or sizes that have Pythagorean rules. The search for mathematical order in Banten culture can be a study that can be integrated into the learning of mathematics in the material of the Pythagorean Theorem. The purpose of this study explores Banten culture, namely the roof of the baduy traditional house, batik leuit cikadu pandeglang motif, banten arch, kasunyatan mosque arch, baduy totopong, baduy weaving thread, and the roof of the great mosque of Banten against the Pythagorean concept. Research methods use ethnographic approaches by integrating theoretical and empirical studies derived from observation and interview activities as data gathering tools. The results showed that Banten culture has various Pythagorean concepts, namely the concept of the Pythagorean theorem in the right triangle, the Pythagorean theorem, determine the type of triangle based on the known side, the Pythagorean triple, the ratio of the sides on the equilateral right triangle. The ratio of the sides of the right triangle with angles of 30°, 60°, and 90°. With ethnomathematical study of Banten culture as a form of strengthening character education on nationalist values by having the competence of love attitudes towards their own culture can grow and be owned by students as the identity of the nation.