Ethnomathematical connections in the elaboration of the mud brick in Salamina -Magdalena, Colombia were analyzed. Theoretically, the work was based on ethnomathematical connections, ethnogeometry and universal activities. The methodology was qualitative exploratory with an ethnographic approach, carried out in three stages: 1) selection of the participant-bricklayer, 2) data collection through semi-structured interviews in the production areas (mud pits and kilns), and finally, 3) a data analysis of the measurement processes was carried out, portions referred to the amount of clay for the elaboration of each brick, emphasizing its geometric shape. We conclude that geometric concepts (rectangle, prism, vertex, parallelism, perpendicularity, angles, etc.), on the stove the parable was identified, and universal activities (counting, measuring, designing, locating, explaining) are identified in the elaboration of the clay brick. Finally, we reflect on the importance of connecting the shape of the brick with geometric concepts such as the parallelepiped and its treatment with GeoGebra, which is a mathematical content addressed in the classroom and suggested by international curricula.