Blora at this time has changed such as conversion of agricultural land and forest land to non- agricultural or undeveloped land that does not pay attention to the terms of the conservation of soil and water and thus potentially lead to land degradation, drought, landslides and disasters flooding which will eventually lead to critical land. From the above problems therefore a study of mapping level critical land.This study aims to mapping and calculate the area of level of critical land in Blora. The methods used in this study are the overlay method, scoring and weighting. According Regulation of the Director General of Watershed Management and Social Perhutani No: P.4 / V-SET / 2013factors affecting the occurrence of critical areas such asvegetation, slopes, erosion, productivity and management.From the result of data processing, Blora dominated by criteria not critical area of 119.672,80 Ha. Most criteria critical in the district areBogorejoarea of 181,53 Ha and most criteria medium critical in the district are Jiken area of 2.441,54 Ha. While the most criteria potential critical in the district are Todanan area of 13.245,71Ha. From the results of assessment of the level of critical land known that the density of vegetation plays a major role in the function of the level of critical land in protected areas outside the forest area, while the level of productivity of land have great impact on agricultural production areas and production forests.