This study aims to determine the mathematical concepts contained in the new grave artifacts in East Sumba. The research method used in this study is qualitative with an ethnographic approach. This research phase begins with data collection, data reduction, data presentation and drawing conclusions or verification. Data collection techniques in this study were literature study, observation, interviews and documentation. The main instrument in this study was the researcher himself and the tools used were observation instruments, interview instruments and documentation instruments. The results of the study show that in East Sumba there are artifacts, namely tombstones. The mathematical concept applied to the gravestone artifacts in East Sumba is the concept of a flat shape. The concept of flat shapes that are applied are triangles, squares, rectangles, trapezoids, rhombuses and circles.